Acacia (Mimosa), grown from seeds
Q. Please can you tell me about Mimosa? I have been given some seeds.
A. Mimosa (botanical name Acacia) hails from the southern hemisphere, predominantly from Australia. This give you a very big clue about the situation it likes, i.e. sunny, hot, tolerant of low rain levels, in fact intolerant of wet ground. The ideal situation for an Acacia would be well-drained soil and full sun. Pruning can be difficult and is best done annually immediately after flowering. It does not regenerate well from old wood.
There are several different species that are best suited to garden cultivation. The three most popular are Acacia dealbata (probably the best known variety), Acacia pravissima which has strange triangular foliage and a weeping habit, and Acacia baileyiana 'purpurea' which has gorgeous blue-grey foliage. All of these varieties have the traditional, fluffy yellow flowers. The toughest variety is A. pravissima while baileyiana 'purpurea' needs the most protection. Suitable for most gardens except the most exposed and the coldest.
Acid soil, how to correct
Q. My vegetable patch has a very acid soil. What can I do to improve it, and do I need to worry about the rest of the garden becoming too alkaline?
A. Traditionally, vegetable gardens are neutral or alkaline. So, if you have acid soil you will need to correct this by the addition of garden lime. It’s important to only apply it at the rate stated on the packet. This is a definite case where you can have too much of a good thing! You will also need a simple soil testing kit to give you a starting point. If you’re putting lime on your vegetable patch it shouldn’t affect the rest of the garden unless you do it on a very windy day. Depending on the level of acidity, annual applications will probably be needed. Correcting the pH of your soil is essential with certain vegetable groups, especially Brassicas.
Agapanthus, sowing seeds
Q. I've just been looking at your website, and I'm wondering if you could give me any advice on the seed propogation of agapanthus. I've removed the seeds from the old flower heads and want to sew them in samll pots. Can you give me any advice or is it fairly straightforward? Is it ok to sew them immediately or should I wait for the seeds to 'dry' a bit, and is there any special seed compost that I should use? Any help at all that you may be able to offer I would be very grateful for. I don't live by the sea, I'm actually in Oxfordshire, but I'm quite successful at growing agapanthus in terracotta pots, and now want to try and increase their numbers.
A. If the seed has been collected freshly from the plant, then it is generally best stored until the spring. What I normally recommend is that you cut the seed heads, stalk and all, put the heads into as big a paper bag as you can get, very loosely tied around the neck so that any seed that falls will fall into the bag but so that plenty of air ventilation can get to them. Don’t be tempted to hang them up in a greenhouse, because whilst you might think that’s dry, it is actually damp. It’s far better to hang them up in a spare bedroom or somewhere like that so that they actually dry and cool and the seed can fall. Almost without exception, most seed of perennials is best sown in the spring in this country when seed is inclined towards germination and plants are inclined towards growing. Whilst in nature seeds will drop and lie dormant all winter and then start germinating in the spring, you don’t get many species that will germinate in the autumn because the temperature is too low. So, I personally would advocate doing it in the spring, I would recommend that it is sown into a proper seed compost, probably a John Innes seed compost: failing that, a multi-purpose one will do because they’re fairly low in feed.
You treat them pretty much the same way as you would any other seed, really, in that you sow them and cover them roughly the same depth of soil as the seed is big. So the general rule of thumb is, if your seed is like dust, you don’t cover it: if your seed is a couple of grains of sugar big, then a couple of grains of sugar depth of soil is what you put on top of it. Water, heat and off you go!Agapanthus are relatively easy from seed – you’ve only got to visit the Isles of Scilly and see how they’ve self-sown all over the place. Nature doesn’t need a helping hand with those ones! Happily go ahead and sow some seeds, but be prepared for disappointments as well as pleasures, because anything that comes from seed is unlikely to be true to the parent, particularly if the parent is a named variety: you will get variations on a theme and you need to be aware of that before you start. With seed-raised plants but it's always fun, you’re never sure what’s going to come out. The offspring of two white agapanthus may not be white, because you can guarantee that some pain-in-the-a**se bee has travelled from a blue one to your white one. You can get all sorts of progeny (a bit like Hellebores, terribly promiscuous little beasts!).
Agapanthus not flowering
Q. How do you persuade Agapanthus to flower? I have some three-year old plants in pots.
Well, you don’t go out and beat them over the head with a stick! Generally, Agapanthus flower better when they are root-restricted, but not always. It’s more important to get the food into them, than to worry yourself overly about ‘is it in a big enough pot, am I doing this or that or the other wrong?’ The important thing is food: they need to have food in the summer and into the autumn in order to produce the dormant flowering spikes for the following year. But you can more or less encourage them if you start feeding them now, you can usually encourage a good flush of flowers for the summer, but you want to make sure that you give them a reasonably high potash feed to encourage flowers to come. People seem to think that they need to be pot-bound to flower well – in which case, I have to ask the question, ‘How do all the ones that are in people’s gardens do so well, where they’re not pot-bound at all?’ You do need a certain amount of maturity with them, admittedly, but having said that, they would do well more or less wherever they are, so long as they’ve got the basic conditions they need, which are: reasonably good, well-drained soil, in full sun. They will not tolerate shade and won’t do well there at all – that will stop them from flowering. In fact, if the clumps get over-congested that can also stop them flowering because the bulbs aren’t getting enough nutrients, so if it’s an oldish clump then that can benefit from being divided, split up and replanted – but then it can take a couple of years to settle down and start to flower again. There is no hard-and-fast rule, unfortunately. I can’t wave a magic wand and say ‘poof’ and your Agapanthus will be in flower! Patience is a bit of a virtue with them. They will flower, and my main recommendation is to feed-feed-feed.
Annuals sown as biennials
Q. Last autumn I bought a collection of annual flower seeds and sowed them in trays in the greenhouse. They came up and thrived at first but then they became leggy and some of them died. What is the best way of growing annuals as biennials?
A. The seedlings need to be pricked out and potted on. Then grow them on in the greenhouse through the winter. Keep the temperature down but frost-free. Keep them growing and then harden them off and plant out in the spring.
Aphids on conservatory vine
Q. We have a vine growing in our conservatory. It was there when we moved in, so it's over twenty years old. Each year it produces grapes, but each year it is smothered in aphids which ruin the grapes and attract flies. What can we do?
A. You need to tackle the aphid problem - but as it's in a conservatory I suggest a biological control, e.g. the more sadistic of you can buy Lacewing larvae! Or you can spray with a non-toxic contact spray: I would recommend 'Just Bug Killer'.
Aphids, avoiding them in greenhouse
Q. Now that we’re all beginning to think about sowing things in the greenhouse or polytunnel, is there any way to prevent Aphids from turning up?
Good hygiene is of paramount importance when it comes to preventing the spread of insects and disease in any greenhouse, and before you start putting anything in there for the spring it is vitally important that you have a really serious spring-clean in there: Jeyes Fluid washed down under the glass, over the woodwork, into every ‘crook and nanny’ that you’ve got in there, because any overwintering insects will then be disposed of and that will give you the best start possible. Any odd pots and trays, get them out – don’t use your greenhouse as a dumping ground – get them out of there and give your greenhouse a nice fresh start. If you’ve got soil in the greenhouse, then make sure you treat the soil as well with Jeyes Fluid and kill any overwintering bugs that may be living in the top of the soil. That’s step one. Step two, when you start putting your plants back into the greenhouse, if you have been overwintering things in there like Begonias, Fuchsias, Geraniums, then when you do your spring clean, sprinkle those plants as well: take them out, knock the top of the soil off, knock all the dead leaves off and again, drench them with insecticide before you put them back in. Make sure that everything is as clean as it can be. When you start sowing your young plants, keep a close eye on them and watch them all the time for the first signs of Greenfly – that’s certainly the most important thing. A lot of people don’t look at their plants enough, so they tend to miss the first signs and once they get a hold that’s when they become little beggars to get rid of, unfortunately. So hygiene and vigilance are probably the most important weapons you’ve got.
Apples for Cornwall
Q. Please can you suggest some varieties of apples that will grow in Cornwall?
A. This depends to what end you want to use your apples. Cider varieties were always more traditionally grown in the west country, but there are some good dessert varieties as well. Ones I would recommend include Cornish Aromatic and Cornish Gillyflower, both are excellent traditional varieties. Of the more modern varieties, 'Meridian' has an excellent flavour, 'Irish Peach' has a distinctly aromatic flavour. And in cooking apples, of course Bramley is the best known, but I would say that 'Newton Wonder' and 'Grenadier' are more reliable in Cornwall. There are plenty of other varieties that do well, I haven't got enough room on this website to list them! A couple of useful sites to visit include the National Trust at Trelissick, Duchy Nursery near Lostwithiel and Thornhayes Nursery in north Devon.
Apples falling early
Q. Why do apples set on my apple tree but then most or all of them fall off in June?
A. There is nothing you can do to prevent it: it is a safety-valve for the plant to avoid carrying too many fruits. It can be caused by dry weather in late spring: but if you know how to prevent that you're a better man than Gunga-Din. Thinning the fruit may help.
Architectural plants for large borders
Q. Please suggest some big, bold plants for large borders.
A.Ignoring trees and larger shrubs, there are many gloriously impressive perennials to really 'lift' your border. A few to whet your appetite are: Cynara carduncularis; the Globe Artichoke with massive silvery grey cut foliage and magnificent thistleheads (to make a Scotsman jealous); Verbena bonariensis, which grows about five feet tall and creates a purple haze of semi-everlasting flowers; Hedychium in variety, but particularly "Stephen", is a member of the Ginger family, with deliciously scented flowers and leaves that will make you dream of Madeira and the tropics with its lush foliage. In the same vein, the Cannas provide vibrant colour, lush foliage and dramatic lines in any border. Also in the autumn, Rudbeckia herbsommer, reaches a magnificent seven feet of brilliant yellow flowers. Finally, I would heartily recommend Tetrapanax papyrifer which has leaves up to three feet across… you can just imagine lying out in the sun being fanned by a willing slave….
Asparagus, how to make an Asparagus bed
Q. How do I start an Asparagus bed?
A. Asparagus beds consist of very well-drained soil but rich and deep. A sandy soil does best for them and they really do benefit from digging in plenty of well-rotted organic material before you start. You must then exercise enormous restraint and not be tempted to pull them in the first two years after planting.
Bamboos for exposed sites
Q. Please could you suggest some Bamboos for an exposed position on the edge of a field?
A.The tougher bamboos can be tricky because sometimes they a little bit on the invasive side and you really need to be very careful that you’re not planting a problem for yourself if it’s going to shoot and sucker too badly. One of the toughest ones is Phyllostachys bissettii which is a very tough bamboo that will tolerate coastal and inland winds and makes a very good screen: but a lot of the Phyllostachys spread by underground shoots and if you don’t want them running into a neighbour’s ground you may need to put up some sort of a physical barrier down in the ground before you plant them. The Pseudosasas are also another good group of bamboos, bigger leaves, maybe not quite so tall but they do produce a good, dense screen. It’s not easy to identify an un-named variety, it’s best to take a photograph and ask an expert. But have a look at the Fargesias, which are big, busy and not very invasive: they do really quite well.
Badgers damaging lawns
Q. How do I discourage badgers from digging holes in my lawn?
A. The only way to distract a badger is to confuse his nose - any physical barriers you put in his way he'll take great pleasure in demolishing. Try using something as simple as Jeyes Fluid on the entry point to your garden, and keep everything crossed.
Bananas from seed
Q. I've always wanted to grow banana trees from seed, but they never seem to germinate. Please could you suggest easy types and tell me the best method?
A. The best variety to grow is Musa basjoo. Make sure that the seeds come from a good source, e.g. Chiltern Seeds catalogue. They do need heat to germinate and will probably need to be in a propagator. Follow normal procedures from then on.
Bay, how to propagate
Q. How do I propagate Bay?
A. Bay, which is Laurus noblis, is best propagated by semi-ripe cuttings taken in mid- to late summer. These should be trimmed and treated with a rooting compound as with any other cuttings, and can be maintained either in a propagator or in a sheltered position outdoors. A note of caution - they can be quite slow to root. However, another method is to look around the base of an established Bay for suckers which can be separated from the main plant by the judicious application of a sharp spade.
Beans for drying and storing
Q.Is it possible to grow beans such as soya for drying and winter storage?
A. The traditional beans for drying have usually been peas or broad beans, but I have to be honest and say that I'm not familiar with the vagaries of soya beans in this country. But most legumes were traditionally stored dried for long keeping and reconstituted for cooking by soaking in water.
Magic Bean - what is it?
Q. Last Christmas our son had a ‘Magic Bean’ in his stocking. This bean had instructions for planting and a promise of a ‘message’ inside, and sure enough when it came up it had the words ‘Magic Bean’ etched into its seed leaves. Anyhow we grow this bean on in a pot and stood it inside the big window of our sitting room. For the last year it’s been growing and growing but with no sign of flowers. Have you any suggestions as to what sort of bean it is and when it will stop and flower?
A. You have me stumped, here! As for variety, I haven’t the faintest idea, and I’d love to know how they get the little message in the first pair of leaves. I have now idea what sort of bean it is but it’s probably been selected for its ability to be ‘manipulated’, shall we say, to have the message put on the first pair of leaves. So I wouldn’t be able to hazard a guess as to variety. If it’s been grown in a pot indoors, it may be that it’s not getting enough light for it to start to flower, but most beans I’ve known would grow very happily in any situation and would start to flower, so I strongly suspect this is one that has been modified in some way, and I’m not entirely sure that you’ll ever going to get much of a crop of beans out of it, is the answer to that. I’ve never heard of it and I’m absolutely fascinated, I’ve got to say, but I think you’ve got me beaten!.
Fibrous rooted Begonias, how to propagate
Q. I have indoors a small, fibrous-rooted Begonia about six inches high. What’s the best way to propagate it and when?
For the fibrous-rooted Begonias, the only way for you to propagate it sensibly is from cuttings. You need to wait until your plant has got some side-shoots on it: if it’s only got one central stem at the moment, pinch it out – if you pinch it back with two or three sets of leaves that can be your first cutting – and then as it shoots out sideways you can take side cuttings off it as and when you want to, really. They’re very, very easy to do. Commercially, they’re done from seed, but the seed is like dust and the word ‘gold’ added on the front is quite applicable! It’s very, very fine seed and it’s quite difficult to get them to germinate without proper conditions like a propagator, so I would normally recommend buying plugs or growing on a young plant. As I say, if you’ve got a particular colour you like, then propagating by cuttings is just as easily done.
Birds, gardens for
Q. We have quite a big garden. Can you suggest some plants to encourage birds?
A. Without taking up all the page - anything with berries will provide valuable food in the autumn, but it's worth bearing in mind that the birds will take red berries first, orange next, and yellow and pink will be last choices! You'll also need to consider providing evergreens for winter shelter. Plants that attract insects will also encourage birds that feed on them. A very good book to give you some hints would be 'Gardening for Wildlife' by George Pilkinton at £4.95, published by Alfresco Books.
Bog garden, how to create
Q. How can I create a bog garden?
If you want to create a 'boglet' or damp area in your garden, the best way of doing it is to excavate the area that you want to make much moister. Get either a heavy-duty plastic sheet or an old pond liner – it doesn’t have to be intact but it needs to be relatively impermeable. Make sure you dig the hole deep enough so that you can dig holes and plant plants in it! – there’s nothing worse than just putting it six inches under the soil, that’s no good at all. It really needs to be 18 inches to two feet down into the ground. Bury your liner in the hole and then perforate it, don’t have it absolutely 100% waterproof because all you’re going to do then is create a slurry-pit! You want the water to be able to seep away but at a slower rate. Then backfill it with soil, don’t use posh compost or anything like that, use ordinary good garden soil. If your own soil’s quite sandy then you might look at bringing in some topsoil from another part of the garden or even buying in a some topsoil, so that you can get a more loamy compost only into the bog area. Then basically just backfill it all up again. You can work some peat in if you want to because peat is a natural bog substrate. Really once you’ve done all of that you can start planting subjects that are going to enjoy a more moist situation. You can then soak the area (although given your average Cornish winter you won’t have to worry about it, but then again, given the average Cornish spring at the moment you may have to!) and the water will be retained in there for a lot longer. It will gradually seep out so it won’t get sour at the bottom – that is the risk if you put a completely impermeable membrane in, it can go sour and soggy right at the bottom. So the water will gradually seep out, it’s not going to rush away. You can top it up occasionally and you have your own happy little boglet. One converse point: if you’ve got a garden where the soil isn’t very soggy but it isn’t very dry ‘neither fish nor fowl’ but you want to make an area moister, try incorporating more peat and organic matter into the soil and anything that will retain moisture, rather than adding grit and drainage: that will up the moisture content in the soil and will increase the range of species you can grow.
Buying bedding plants in winter
Q. There are bedding plants in a well-known chain store. Surely they can’t really be put outside in this weather? (mid-February)
A.Very true, they can’t! Unfortunately, a lot of nurseries and, more, garden centres, tend to jump on the early bandwagon for bedding plants. They will either sell them as these trays of young seedlings which you can take home and plant out for yourself, or in fact they’ll have bedding plants to sell. No way, José, should they be put out yet! It’s only the beginning of February, for heaven’s sake so we’ve got another two months with a risk of frost, even in Cornwall. I certainly wouldn’t even consider putting out summer bedding yet. Spring bedding, yes: Polyanthus, Pansies, Forget-me-nots, Violas – all those sort of things are fine – hardy bedding is fine, but tender bedding – you shouldn’t even be considering it yet. If you see them in the garden centres and think ‘Oh, I’ll get an early start’, the chances are you’ll be buying them again in two months’ time. I wouldn’t even consider selling summer bedding yet for at least another six weeks.
Black Bamboo, where to grow
Q. What is the best situation for growing Black Bamboo?
A. Quite a tolerant plant, this, but it will be happiest in moderately moist, good soil. Having said that, it is quite tolerant of a range of conditions. So it's worth experimenting with. To show the stems off to their best colour, I would recommend growing it in a semi-shadey or sunny position with a light background. In full shade you will lose the effect of the stems.
Black Bamboo, problem with
Q. I have a Black Bamboo which is struggling, it’s hardly replacing its leaves. Any suggestions, please?
If you’ve got a bamboo that is obviously struggling, then the chances are that there’s something deeply unhappy at the root. Depending on how long it’s been where it is, it may well be worth considering moving it to another situation. If it’s in a pot then I suspect it’s struggling because it’s in the pot – possibly drainage issues, difficult to say, but I would recommend that it is moved out of the pot and planted into the ground. Ideal conditions would be moisture-retentive, but not boggy, soil; some protection from the worst of the wind; it actually grows quite well in sunny shade, but be careful where you put it because if it’s too shadey you’ll actually lose the effect of the dark stems – you need to have a light background to show it off properly. It does benefit from fairly rich soil, so I would make sure you incorporate well-rotted compost into the soil before you plant it out, but it certainly does appear that if it’s struggling in a pot, I’d say there’s something fundamentally wrong with the conditions that it’s in.
Blackfly on broad beans
Q. Most years I get blackfly on my broad beans. Can you suggest how I can prevent it, or failing that, treat it?
A. Once you've got it, personally I prefer to use a more natural control which you should be able to get from your local centres. One is called Organic Pest Control, but the cheapest option is to buy Savona which you can then dilute and use quite safely on all food crops. Avoiding it in the first place is very difficult unless you use a complete barrier to prevent infection, e.g. horticultural fleece.
Q. Can you recommend some blue plants for someone who likes everything blue?
Blue-flowered plants are relatively easy, although there are those who say horticulturalists are colour-blind and their ‘blue’ is most people’s purple! One of the most popular groups of blue flowers would have to be the Ceanothus which gives gorgeous flowers in the spring and summer. Ceratostigma willmottianum is another of my favourites, and there’s a very good new variety called ‘Forest Blue’ and there’s one called ‘Desert Sky’, which are particularly lovely. I think another of my favourite groups of plants with true-blue flowers would be the Pulmonarias, which are the Lungworts – they have gorgeous flowers ,
very early – in the late winter, almost . They're a herbaceous plant, particularly attractive, I’m very fond of those. But probably my favourite flower would have to be the Meconopsis – the Himalayan Blue Poppy: this is a plant which my mother could always grow very well in her garden. I’ve given up trying to kill them now: I can’t grow them in my garden, they like those mythical conditions of well-drained, moisture-retentive soil. If you can grow them, they’ll love you and they’ll self-seed and they’re beautiful in the garden. If they don’t love you, you’ll end up fighting an uphill battle to grow them.
So those are probably my favourite blue flowers.
Now, when it comes to foliage, that’s a little bit more tricky and I suppose really, in honesty, you’re looking at a sort of glaucous-y foliage rather than truly blue. One of the more unusual ones which is worth looking at is the Fothergilla, which is normally grown for its autumn colour, which is absolutely gorgeous and it’s a member of the Hazel family. Fothergilla gardenii ‘Blue Mist’ has lovely glaucous foliage.
Then you can look at the more Mediterranean-looking plants, particularly some of the palms: Butia armata is a very handsome, almost a blue version of the Phoenix palm with a lovely, steely-blue foliage to it. The other palm which is well-worth looking at is the blue Chamaerops: most people know the Chamaerops humilis which is a fairly hardy, dwarf fan palm, but the blue version of it, Chamaerops humilis 'Cerifera' is, again, very handsome to look at and quite striking. It stands out well and is very popular with landscape designers for doing coastal gardens. Those ones work particularly well, so you’ve got quite a good range.
Blueberries in exposed sites
Q.How salt-tolerant are Blueberries? Would they grow in open ground?
I wouldn’t say that Blueberries are my best choice for growing in an open position. Of paramount importance for Blueberries is the soil – it has to be extremely acid and it needs to be moist, so it doesn’t want to be in soil that dries out readily, particularly during the summer. And in all fairness, unless you live in a very acid, almost boggy moorland area in Cornwall (or most coastal areas of the country) they are generally best grown in pots where you can control the environment for them much more easily. But it’s not one I would recommend for an exposed coastal situation. Having said that, Billberries, which grow wild on moorland areas, have been known to grow down to Scottish sea lochs, along the cliffs and coastal areas of Scotland. So, I don’t really see any reason why Blueberries shouldn’t, it’s simply that I haven’t seen them in that situation. But as I say, the critical thing is the soil and the moisture.
Bonsai trees, how to start a collection
Q. What’s the best way to start a Bonsai collection?
Probably the easiest plant to start off a Bonsai would be a small, deciduous tree. The purists would start them off from seed so that they could start training them from a very young plant, but you can buy a young whip or a young seedling quite easily; and if you get something that is very flexible like a birch you can start to twist it and bend it to your will quite easily from a young plant. Some of the favourites that are used are in fact Birch and also Acer campestre – the Field Maple – is a popular one, and of course the Pines. Unless you’re a dab hand at it you can find you’re stripping the bark off half one side of it so that there’s this tiny strip of bark supporting life at the top of this tree. So you can very easily buy a seedling of a tree, or you can find seedlings growing around in your garden, very often, and you can dig up one of those and start off with them. But don’t go for something like Beech or Oak because they’re too slow-growing: if you want to get a result quickly with your first Bonsai, go for something a little bit quicker. And of course, if you buy something like a dwarf conifer, particularly one of the Chamaecyparus obtuse group of conifers, they’ve got naturally twisty, bendy stems and they have a slightly Japanese-y look; with judicious pruning-out you can start off with a fairly ordinary-looking conifer and, half an hour later, end up with something that looks like it’s spent a hundred years growing into that twisted shape. So that’s quite a fun way to start, as well. You need to trim the roots and you do need to splay the roots out as well: they don’t grow Bonsais in the sort of pot you’d grow a plant in ordinarily, they’re grown in wide, shallow pans which, again, restricts the height and growth. But if you’re taking a plant that’s been established in a pot and you’re wanting to splay the roots out, be careful not to damage them too much, because obviously you are pulling the root system apart – gently does it! As for compost, you can buy Bonsai compost and it’s probably best to do so because they need a very low nutrient compost: you don’t want to encourage vigorous growth, so get the right stuff for it. If you go for something hardy, they can live outdoors. You can also find houseplants done as Bonsais and they must be kept indoors, but virtually everybody who grows Bonsai, if they put them outdoors they put a lid over the top – so they won’t be heated and very often they haven’t got sides on whatever structure they’re in – a bit like a leanto, I suppose; but they do try to keep the worst of the rain off because they haven’t got the root system to support the same level of rainfall that most plants could cope with.
Box, fungus in
Q. I saw something recently on a TV gardening programme about Box hedges being affected by a fungus. As I'm intending to plant a box hedge I am wondering whether this is a new problem and whether it can be controlled?
A. The problem you see is called Box Blight and has been around a long time. There seem to be two different types and there are varying opinions on how best to treat it. Basic treatment involves cutting out affected areas, and the plant will normally regenerate. Obviously in an established hedge this can be dramatic but it may be possible to spray preventatively with a fungicide. It isn't usually a serious problem but if you've got a knot-garden it can cause serious problems. There are no quick or easy answers, I'm afraid.
Brachyglottis repanda, problems with
Q. I have a Brachyglottis repanda. It’s been living outside, it looks extremely miserable with purple marks and holes in the leaves. Any sugguestions?
Brachyglottis repanda is one of the less hardy members of the family and really does need to be in a very mild, frost-free coastal area – which, unfortunately, we can’t always provide to the extent that we would like to. Now, if it’s still got foliage on this is a good sign; if the foliage is marked and spotted and purple and it’s looking sorry for itself, I’m not in the least bit surprised, given the winter that we’ve had. What I would suggest is, if it’s in a container, then I would be tempted to give it a spring holiday, if you have a greenhouse or a conservatory, take it indoors, give it a bit of TLC and it will, hopefully, perk up again. If it’s in the ground outdoors, then what I would probably recommend is that you have a good look at the plant, if the stems are looking relatively OK I would give it a light haircut – don’t cut back into old wood, just take off some of the tips, and encourage it to send out new shoots. If it can do that, then hopefully it will regenerate and recover. It’s been a very cold, very wet, very miserable winter and that’s almost certainly what it’s suffering from, because as I say it’s not as hardy as ones like ‘Sunshine’, ‘Monroi’ or ‘Rotundifolia’.
Burglars, plants to deter
Q. Can you recommend plants that will deter burglars?
A. In this case you can be quite vindictive without anybody being able to tell you off! In fact, police recommend it. Some good ones to consider include: groundcover roses, Berberis - especially B. x ottawensis "Superba" - hollies of all descriptions and gorse. If you're feeling really nasty, as well as wanting to create a desert effect in your garden, plant Agaves and Puyas as they have backward facing teeth. Having caught your burglar you can then select your chosen method of punishment! Basically, any prickly plant will do.
Brassicas, Club Root in
Q What can I do about Club Root in Brassicas, short of moving to another vegetable plot?
Club Root normally comes about when you have been growing Brassicas in one area for too long. It can be treated by a variety of methods. First and foremost by not growing any more Brassicas in that area for several years, so yes, rotation is one answer and would certainly be the best choice, with a minimum rotation of four years. But you can also look at increasing the lime content of your soil to help counteract Club Root. Also, incorporating Mycorrhizal fungi into the soil will help to stop it: you can now buy them from most nurseries or garden centres: they come under the trade name of ‘Root Grow’. One of the things that people sometimes do is to grow their Brassicas in pots to start with and plant them out when they have an established root system which will support them even if they do get Club Root afterwards. But really and truly, it’s good husbandry and good crop rotation which should hopefully help keep Club Root at bay.
Butterflies, encouraging them
Q. Please can you suggest some plants that will encourage butterflies into my garden?
A. To start with, the obvious and well-known one - Buddleia in all varieties. Also consider Sedum (whether Alpine or perennial variety), Clethra - Sweet Pepper, Caryopteris, Berberis (valuable for early spring pollen), Heather for all seasons, Perovskia - Afghan Sage - and virtually all culinary herbs. There are plenty more but I don't want to fill up the website with one long list!
Cannas, how to grow
Q. How do I grow Cannas? I’ve never tried before.
A. Cannas fall broadly into two categories: hardy and non-hardy. Non-hardy are probably the commonly recognised ones and are best described as ‘tropical looking Gladioli’, in that they stand up, they’ve got a big spike of flower, huge foliage with leaves reminiscent of red or streaky variegated – almost banana-like – leaves. They’re very often used, unfortunately to their detriment, in municipal planting schemes on roundabouts in seaside resorts which tends to put people off them sometimes. But for all that, they are wonderful, lush, exotic plants which will ‘lift’ any planting scheme or border, and I think are well ‘worth the candle’. If it’s those ones that you want to try growing, you generally buy them as dry corms during January, February or March. From March onwards you would buy them as a growing plant in a container. Either works just as well, it depends on you, really – your time, budget and green-fingeredness I suppose, as to which you go for. The key things to remember with all Cannas is that they like lots and lots of food and they do prefer a soil which doesn’t get dusty-dry. They will be far better in a soil – I’d like to say – moisture-retentive but well drained – mythical conditions! But they don’t want to be in a very sandy soil that’s dry all the time, they’re much better in a humus-rich soil that will retain some moisture without getting water-logged – they don’t enjoy boggy conditions, it’s very true. Once they’re established in that sort of conditions, they like to be well fed – they’re quite hungry feeders. So either make sure that you incorporate some well-rotted manure into the soil before you plant, or you can mulch with well-rotted farmyard manure or you can just continue to liquid feed: any method will do equally well – but get the food down them, basically, they do like regular feeding. Then they’ll provide you with plenty of lush colour both in foliage and in flower, right through the summer. But if we’re keeping an eye on them, because there are some varieties that have got viral infections in the foliage – if you get this sort of mottling, patterning on the foliage – it can mean that you’ve got a virus, it’s worth keeping an eye on them. It’s particularly disfiguring in the variegated varieties, so do keep an eye on them, it’s well worth watching out for that.
Now with the hardy varieties, probably the best one is Canna iridiflora eckmanii. This one really does look like a Banana growing outdoors – it’s a wonderful, great thug of a plant. I got my first snip of it from the head gardener at Lanhydrock, who very kindly dug me up a piece. Mine grows regularly to six foot in the garden. But it is hardy. Having said that, it needs protection to overwinter properly because unfortunately it won’t actually get going in the spring, very often it’s so slow because of the cold winters or wet winters or whatever it might be which stop them from getting kick-started early enough: quite often it’s September or October and we’re almost heading for the first frost before it actually starts flowering! So what I’ve done with mine is that I usually lift half of it, leaving half of it in the ground, and put it in a pot in the greenhouse just to get it off to an earlier start – it’s only a cold greenhouse, there’s no heat protection – but it gives them a bit of an earlier start, you can get them planted, and if you get them out early enough and growing well, usually you would expect to have flowers from the second half of July and then it will carry on flowering right through until the end of the autumn. But the difference with that one is that the flowers hang: you have a spike of flowers growing up but the flowers on it hang down, whereas with the traditional Cannas they stand up like a Gladioli.
The non-hardy varieties and the hybrids need to be wintered indoors in a frost-free greenhouse or polytunnel which suits them well. While I say ‘frost-free’, in all honesty, as long as we keep them on the dry side, they’ll take a degree or two of frost, but if they’re soaking wet and frozen cold then they’re not going to be happy bunnies. So if you can give them that little bit of protection, it’s surprising what you’ll get away with. And then in the spring, if you’ve lifted them and put them into trays, lift them out of the trays, put them into nice big pots with fresh compost, get them off to a good start, ready to plant out again in the summer. Hardy varieties can stay outside in winter: as I say, I divide mine in half as an insurance policy, put half in a cold greenhouse (a) because it starts off earlier and (b) just in case it’s such an evil and horrible winter that the original plant doesn’t survive.
Cactus, growing out of doors
Q Can I grow Cacti outside in this country, and if so, what soil do they like?
A. Cacti outdoors in this country are in all fairness a non-starter. It's not the cold that does for them as in their native climes they withstand sub-zero temperatures: it's the rain that kills them over here. So the only way you could grow them out of doors would be with some sort of cover to keep the rain off. As a rider, I would suggest succulents such as Agaves and Aloes if you want to create that look with slightly fewer vicious spines. Any soil for Cacti must be free-draining. From the salt point of view, they are actually quite tolerant but drainage is the key issue.
Callistemon, becoming 'leggy'
Q. I have a Callistemon which is about four feet high. Is it normal for it to lose all its lower leaves?
A.Yes, I’m afraid this is just something that Callistemon do! People buy a Callistemon and then are rather disappointed that it loses its lower leaves and acquires the ‘bare bottom’ look. And if you attempt to cut it back to the old wood, it doesn’t like it. I would suggest that as soon as it’s finished flowering this year, you look at giving it a haircut – a gentle haircut, don’t go back into old wood, but enough to encourage some more new growth to fill out and, hopefully to cover up, that bare bottom. But it is a natural consequence and it’s not something that you’re going to be able to completely get rid of. Cutting it back, keeping it fed and well-mulched so that it doesn’t get too dry (despite the fact that it will cope with very dry conditions), all of those things will help it to hold its foliage at the base as long as possible
Camellias, how to choose early-flowering varieties
Q. Can you suggest really early varieties of Camellias – the ones that are in flower now (January)?
The very early ones are the sasanqua varieties which are the winter-flowering Camellias; they really started flowering before Christmas. Ones like ‘Narumigata’ which is a lovely pink-and-white stripey one, and ‘Rainbow’ are beautiful. ‘Hugh Evans’ is another good variety with a gorgeous perfume on it. The sasanquas do have quite a nice perfume with them, unlike the spring-flowering Camellias – the williamsii and the japonicas. Of the main-stream Camellias that are starting to flower now, the williamsii that come out first generally the single ones will be first out in the rush, like ‘Cornish Snow’, ‘St Ewe’ and ‘Bow Bells’ – they’ll be the first ones showing their colours. But be careful with the very early ones, because if we do get a hard frost, it’s inevitable unfortunately that the flowers will get clobbered! If you’ve got a Camellia that looks like it’s got the potential to get straggly, don’t be afraid to give it a haircut immediately after flowering. Last week I was in Italy on a plant-buying trip, and they had plants down there to die for – including standard- and pyramid-clipped Camellias: they’ll clip anything that stands still for long enough! But really so full of buds and yet they were clipped into pyramids. So, prune them back immediately after flowering and you can keep a much denser, bushier plant.
Camellias, how to grow
Q. Can you tell me how to start growing Camellias, and the best early varieties?
A. Camellias are probably one of the easiest plants to grow. You’ve got two main options: you can grow them in the ground, you can grow them in a container. Obviously, if you’re going to grow them in the ground then they would need to be in an acid soil. Particularly in Cornwall and in parts of Devon, we have mostly acid soil, but if you’re not sure, do do a soil test before you plant them. Having said that, they make superb container plants and again, if you’re in a limey, hard water area then just collect your rainwater and water them with that, rather than with tap water. They should be quite happy, you shouldn’t really have an issue with this. If you’re going to grow them in containers, make sure that you do pot them up in ericaceous compost though as they will require an acid compost to do nicely. They are plants that are best grown in shade or sunny-shade because they don’t enjoy getting baked in the summer. They’re happy in some sun, but not to get absolutely cooked by it. The only other positioning factor that normally concerns them is, it’s best to avoid the morning sun: it’s not that the plant itself is affected by it, it’s that if the flowers have got frost on them in the winter, the morning sun de-frosts them very quickly and they’ll then spoil. So, it’s sort of an old wives’ tale but it’s there for a practical reason, so try to avoid the morning sun for them. Afternoon or evening sun, no hassle at all.
As for variety, the sky’s the limit. There are so many lovely varieties and they’re already starting to flower, particularly down here I’ve seen loads of them out. ‘Bow Bells’ is probably one of the prettiest early ones, along with ‘St Ewe’: both of them are single. C. japonica ‘Little Bit’ is already out in flower. A lot of the ‘Williamsii’ varieties are generally the earlier ones, whereas the japonica varieties tend to be in the second tranche of flowering. But that’s not always true, there is quite a big overlap. But the very, very early ones are the ‘Sasanqua’ varieties which are the winter-flowering Camellias: some people call them autumn-flowering because they usually start flowering before Christmas and a lot of them are quite sweetly-scented as well. If you wanted some very, very early, say around Christmas time - December and January - then they’re ones that are well-worth looking out for – ‘Nurumigata’ and ‘Jean May’ are two particularly nice ones, but ‘Burgundy’ is also very pretty. But there are, literally, hundreds and hundreds of varieties: we’ve got about a hundred-and-fifty varieties in our nursery at the moment, working up to a range of about four hundred which we’re hoping to aim for in the next couple of years. And they’re all so collectable and gorgeous. But I suppose that, if I had to pick two favourites I would go for ‘EG Waterhouse’ and ‘Margaret Davis’ – and I’d probably have a third runner-up of ‘Desire’. But they’re all such wonderful, wonderful plants.
As for diseases, unfortunately Camellias are susceptible to Phythophthera remorum, which is the Remorum Blight or Sudden Oak Death and they’re one of the notifiable plant groups which are susceptible to it. But in most people’s gardens, even in areas where Remorum has become a problem, I’ve never yet found it in a private person’s small garden. It’s in private, big gardens, i.e. in gardens that open up to the public and gardens that are acres and acres – it has been found in some of those – but generally it’s come in on something like Rhododendron ponticum, or come from another source. Because they have such a big, thick, waxy, leathery leaf it seems to take them quite a while to get an infection. And even if you do get Remorum Blight and the plant dies (it will eventually kill it), the chances are you won’t infect anything else unless you’ve got nothing but Camellias in your garden, because it’ll die, you’ll notice it’s died, you’ll get it out of the garden, you’ll clean up all the dead leaves and it will have gone anyway. Tthat is the best method for getting rid of the problem. So that’s the main disease that affects them. They are also affected by something called Bud Blast, that’s when the buds fall in spring: before they open they go brown and drop off. It’s a disease that’s been around in Camellias for a long time and the way to prevent it from recurring on your plant is – when the flowers fall off, a really good hygiene policy is to pick up every flower, every petal, from around the plant and get rid of them. Don’t compost them. Any fallen leaves – get rid of them, because what will happen is that any buds with Bud Blast that drop off will harbour the spores and they will bounce back up on to the plant again if they’re left there. So good hygiene will keep that under control and it shouldn’t be a problem. Other than that, they are very tolerant, very easy plants: all they require is a bit of food, a bit of water and a bit of TLC.
How to propagate Camellias
Q. How do you propagate Camellias?
Traditionally, Camellias are propagated by cuttings, and I suppose in fairness most people have best success using traditional heel cuttings. To do that you would need to do semi-ripe wood cuttings which are usually done around the end of June or July time, when you’ve got a reasonable amount of growth on there – the bit you’re looking for is between where it’s brown and where it’s green – that’s the semi-ripe bit. If you’re going to do a heel cutting then you need to pull a little side-shoot down off the main stem. Trim the heel back, trim off the bottom pairs of leaves, stick it in rooting powder, pop it into some well-drained compost – and off you go!
But you can also put them into the ground, if you want to. You need to prepare a bit of soil, ideally somewhere that’s semi-shadey, somewhere that you can keep watered and which is a bit sheltered. Generally, you would dig a trench: very often people cover the bottom of the trench with sand or coarse grit. Do your cuttings exactly the same way I’ve described, put them against the side, backfill it with soil, give it a good drink and walk away. You’d be looking about 12 months for those ones I suppose to root: Camellias are fairly slow rooting. If you do them in a propagator, you’re still looking at six months for rooting, if not longer: but in the ground you’re talking of about 12 months.
A fun way you can propagate Camellias, if it’s a biggish bush you want to do, is to take air cuttings. To do this you need to get some Sphagnum moss, which you can buy in local centres. Try and buy some environmentally friendly moss if you can, not something that’s been dragged half way round the world – you can buy it from licensed sources, so try to make sure you’ve got some of that. You want to make an incision into the stem – not a huge stem, you’re looking at doing this with af side shoot again – what you need to do is to cut more or less halfway through the stem but not all the way through. You pack the Sphagnum moss around with a little bit inbetween the gap that you’ve cut: then you wrap the whole thing up in Clingfilm or some form of plastic, sealing it above and below the cut. You’re making a lump of moss about the size of your fist around this cut – wrap the whole thing up in plastic, make sure it’s nice and moist in there, and walk away. Hopefully, the Camellia will root into the Sphagnum moss, but of course it’s still got its umbilical cord to the parent plant. So it’s rather like layering a rose under ground but you’re doing it up in the air. Apart from the fact it’ll look as if your Camellias has got some rather strange growths, it’s quite a nice way of propagating them! So you’ve got all these methods for vegetative propagation.
Of course, on top of all that, if you really fancy a giggle, try doing them from seed. That’s somewhat more hit-and-miss, there’s no guarantee what the results are going be, but if your Camellia does set a great big, fat, juicy seed pod, try sowing some Camellia seed. They will probably need stratifying, which basically means beating them up with some grit first and then stuffing them in the fridge for a few weeks until they’ve been cold-treated. Take them out, sow them in a propagator and wait and see what pops up! But bear in mind you’re going to be waiting a few years to see what the flowers are like. There are species Camellias but there aren’t many of them around: I’ve got to be fair and say that for my money they’re for the purists. Really the best ones nowadays that you’re looking at are the hybrids now – and they are superb.
Probably the one that people like to grow at the moment is Camellia sinensis – for those who like to grow their own green tea and like following in Tregothnan’s footsteps. It’s quite a sweet little bush with a very small white flower – but don’t plan to be picking enough tea to be starting up your own production unless you’ve got an awful lot of acres to spare!
Cannas, how to overwinter
Q. How do I overwinter Cannas?
A.Cannas are best overwintered in a small greenhouse or conservatory without too much heat which could precipitate premature growth. I prefer to wait until the first frosts have killed off the foliage before bringing them in. They can then be overwintered in very much the same way as you would Dahlia tubers, but keep them in the posts of compost and don’t allow them to dry out completely. Then in about February, knock them out of their pots, shake off the old soil as far as is sensible, and re-pot them into fresh compost. Give them a good drink to initiate growth and they should be on their way. When you do re-port them in the spring this is a good time to do any dividing and get some babies for free.
Carrots, last time to sow
Q. When is the latest time to plant carrots?
A.The end of September would probably be the limit. You will almost certainly get smaller crop production and they will take longer to mature, but should be none the worse for that. Normally, August would be the latest month to sow carrots, with the maincrop in June.
Cats, keeping them off seedbeds
Q. How can I stop other people's cats from ruining my seedbeds?
A. This is a perennial problem for gardeners and the solutions are varied. Firstly, remember that cats are highly sensitive to smell, so anything that marks or detracts from the remains of their previous spoors will help to discourage them. One of the best things is to get a bar of the cheapest whiffiest soap you can find and grate it up. Unfortunately at this point you have to clear up any cat mess that has been left before you sprinkle the grated soap over the area you wish to protect. Another simple method is to push short canes into the ground at 6-9 inch intervals and then weave cotton betwixt and between them to make a convoluted grid. There are more expensive options on the market such as water sprinklers with motion detectors. Or one of the most novel approaches I have seen is a small plastic frog which croaks when you approach it. If your cat has a nervous disposition, it will soon go elsewhere.
Q. I have a Coronilla emerus. Nobody seems to know much about it, although it's mentioned in a book 'The Seaside Gardener' as having been grown since the 16th century.
A. Coronilla emerus certainly isn't the best known of the Coronilla family, and in my view is not the showiest of the family, although it is a pretty plant. I would recommend Coronilla glauca or C. glauca "Valentina", which flowers very freely and smells deliciously of coconut.
Carrot Root Fly
Q. What is the best way of protecting carrots from Carrot Root Fly?
A. The best protection is the barrier method! Carrot root fly are afraid of heights and rarely fly higher than two to three feet off the ground. So a simple method would be to press bamboo canes into the ground and drape horticultural fleece over them, thus preventing access.
Caterpillars on brassicas
Q. Every year caterpillars eat my brassicas to bits. What can I do about it?
A. Cabbage White butterflies? - you have two choices. Either spray with a contact insecticide which is safe to use on edible crops, or a more satisfying, but more time-consuming, method is to pick them off by hand and squash them!
Children and gardening
Q. How can we get our small children interested in gardening?
A. As soon as they're able to take an interest in any topic, is the time to start. There are some fabulous garden tools and accessories on the market for children, as well as garden starter kits which will help to foster their interest. Depending on the age of your child you could consider persuading your local junior school to start a gardening club. It is important to encourage respect for plants at an early age if we are ever going to combat rising vandalism.
Chili Peppers, using collected seed
Q. If I sow seeds out of Chili Peppers, will they breed true?
A. As with all seed taken from any fruit or veg you buy in a shop, there is always the chance that it has cross-pollinated with something else. So there's no harm in trying your seeds but don't blame me if you get some interesting results!
Christmas presents, books for
Q. Can you recommend some books to give as Christmas presents?
A. For most gardeners, Christmas can be a time of torture because they feel trapped in the house and they can’t get out. So, give them their own little escape valve and buy them a lovely, lush gardening book. Even if it looks like a coffee-table book, there’ll be ideas in there and things in there which make most gardeners start to go all slobbery about the chops! Even just a new, up-to-date Plantfinder is very often a very welcome gift to receive. But there are some beautiful books out there now and at some very attractive prices. So you can reward the gardener in your life with a good range of books, ranging from ‘Fifty Ways to Kill a Slug’ which I think is a very fun book and particularly if the gardener you know gets very frustrated by slug damage; through to some beautiful design books, books on plant association, recycling in the garden, how to make different ornaments, how to use natural willow in the garden, down to the ordinary plant encyclopaedia type of books, which inevitably – it doesn’t matter how many books you look at – you will always find new plants you haven’t seen before. The big RHS dictionary is a very good buy, as is the Readers Digest, the Hilliers Illustrated Manual is an invaluable resource. There’s a wide range of specialist books on individual topics, and again if you know that somebody is very keen on a particular group of plants, sometimes it’s nice to buy them a book dealing with that particular topic, whether it’s Magnolias or Fritillaries or Irises or Dragonflies – whatever 'pops their candle' !
Q. Please can you suggest an original kind of Christmas present?
A. Something which can stretch to any budget for a gardener is to arrange a day out, and it sometimes is quite nice to choose a garden that the gardener in question hasn’t been to before and arrange for a ‘mystery day out’, to take them out for a day to visit the garden – or maybe make it two gardens. The fee can be as outrageous as the budget will allow, but gardeners like nothing more than to arrange a nice day out, having a look at what other people have got, and gleaning ideas, and it makes a lovely and relaxing present – in fact I’d like somebody to buy me one! One of those opportunities where you can make up your own present – you can make it into a little voucher and say ‘it’s to be redeemed at your pleasure’.
Christmas plantings of trees
Q. Can you suggest trees to give for planting at Christmas?
A. If you’re still looking for a last-minute Christmas present for the gardener in your life, there are quite a lot of things that you could look out for. Probably I wouldn’t suggest a houseplant at the moment, because your house is probably stuffed to the gunwales with Christmas Trees, decorations, cards and everything else. So maybe it would be quite a nice idea to give them a reason for actually going out in the garden on Christmas Day. So why not give them a tree to commemorate Christmas? Personally, I’d like to plant a tree every Christmas Day, and this year I’m hoping to plant an Elm tree of a newish variety which has come to us from France, which has for twenty years been grown in an area where there is known Dutch Elm Disease and has shown 100% resistance. So we’re hoping to help introduce it to this country more widely: it’s called Ulmus lutèce which looks very much like our native Elm which is virtually extinct, tragically. It would be great to see them coming back into our landscape again. So we’re hoping to plant a small group of them in our field this year, weather permitting, on Christmas Day.
Christmas presents,useful tools for
Q. Have you any suggestions for practical Christmas presents?
A. If you're stuck for a present for the gardener in your life, you’ve got several choices of direction. This week, we’ll look at practical presents. Depending on your budget, I’ve yet to find a gardener who would not appreciate a good stainless steel spade (or spade and fork), all nice and shiny with a big red ribbon on. Bear in mind, if you’re buying for a lady gardener, I personally find a border spade and fork better, and if your garden is very small, a border fork and spade fit in amongst the other plants more easily. But the guys like the big ones: I think it would be better if I don’t comment any further!
Christmas Trees to keep
Q. For people who want to choose a rooted Christmas Tree to grow on outside, and who find it a bit depressing to throw out a tree each year, is there a tree or a substitute Spruce that will grow on?
If you don’t like the idea of buying a Christmas Tree that has to be thrown away at the end of the Christmas period, be careful if you are tempted by the idea of buying a ‘rooted’ Christmas Tree. If it’s a large one, over four foot and rooted, it will have been dug up, it will be very roughly rooted and unlikely to have a root ball – its chances of survival are not high, although many people do get them to grow if they keep them moist and keep them indoors for the shortest possible time.
But if you want to have a plant to use as a Christmas Tree, and keep it outdoors for the rest of the year, there are quite a few varieties you can go for. Now, if you wanted to be traditionally English, you would in fact go back to a Holly – you could grow it in a pot and bring it indoors for the Twelve Days of Christmas, but keep it indoors for the minimum length of time, and also don’t stick it next to a roaring fire or central heating radiator. It needs to be kept in a cool room, and moist while it’s indoors. If you want to go for a traditional conifer type, it doesn’t really matter what variety you go for, you want to go to your local centre and have a look at the ones that are pot-grown – and be careful that they are in fact pot-grown and not dug up and stuck in a pot. There is a difference and the ones that are just stuck in a pot again may well just be rough-rooted and may not be guaranteed for survival so check when you buy one, if the company happily guarantee the plant, you can be fairly sure that it’s been grown to live and not just dug for Christmas. And then it’s down to personal preference really, what variety you want to go for. ‘Non-drop’ Christmas Trees are all popular – the Abies nordmaniana and Abies procera always make good Christmas Trees, but the Picea abies is the traditional Norway Spruce that so many of us use – a prickly little beggar but makes a lovely smell in the house. There is also Abies koreana, very slow growing but with lovely blue cones on them when they get more mature, which people quite like to use. Pinus contorta which is in fact a traditional Christmas Tree used in Scotland, is a popular choice as well, but it does tend to grow rather quickly and leggy: probably difficult to grow a good one in a pot if you wanted to use it for Christmas. The choice is very, very personal.
Cistus ladanifer, going leggy
W. I have some Cistus ladanifer which have become very leggy. Should I cut them back to make them bushier?
A. Cistus don’t like being cut back hard: they’re far better cut back regularly as a young plant to stop them reaching the point of becoming very leggy. Cistus ladanifer is a relatively tall variety and once it becomes leggy you’ve got two options: one is to wave goodbye to it and the other one is to plant something in front of it to cover up the legginess. Obviously this will depend on the situation where you’ve got it and which you decide you want to do with it. But cutting it back hard to encourage new growth unfortunately is a non-starter with Cistus.
Citrus fruit, how to grow
Q. How do you grow Citrus fruit?
Citrus are actually remarkably easy plants if you bear in mind where they normally grow, which is on poor, mountain soil in Mediterranean countries. This give you an indication of what they really would benefit from in terms of growing conditions over here. It basically means that they need to be kept dry, and that is the main reason why they’re overwintered under glass in this country, because we don’t do ‘dry’ in the winter over here! – much as I wish we did. So ideally your Citrus want to be outdoors during the summer, so I would normally say from the end of April or beginning of May until October. Put them outdoors on a sunny patio, somewhere where they’ll get the best of the sunlight and if we’re suffering from torrential downpours you can pull them back against the house and protect them from the worst of the rain. They will benefit from being outdoors during the summer and once autumn sets in, wheel them indoors again. Cold greenhouse, cold conservatory, or pamper them in a heated one if you wish to but they’ll grow just as well in a cold one but you won’t get them into flower quite so early if they’re in a cold greenhouse or cold conservatory.
Feeding for Citrus is pretty easy if you follow two basic rules: from September to March you use ‘Winter’ feed and from April until September you use ‘Summer’ feed. It’s that simple! They like to be fed, you do need to have the two different nutrient make-ups because in winter they’re not actively growing but they tend to be putting on flowerbuds, so make sure that you have the two different nutrient feeds for them. And, critically, in the winter, again because of where they are, if it’s a cold greenhouse or conservatory, do not over-water them – they don’t like to be excessively wet at the roots during their more dormant period. So keep an eye on them.
Now from the point of view of pests and diseases, the biggest culprit is usually mealybug or woolly aphid, and you’ll get that in the crooks and nannies inbetween the stems. The other really bad news is scale, like little round discs on the underside of the leaves: if you squidge them you get a goo out from them which is the insect. They are notoriously difficult to get rid of. If it’s a small infestation, cheap alcohol (one of the ones you don’t mind wasting half a teaspoon of), put it into a teacup, get a cottonwool bud, dip it in and then dab it on to the insects: that works for mealybug, woolly aphid and scale. It doesn’t make them drunk, it dehydrates them, so they don’t have a happy ending. But you can obviously get proprietory sprays, but with scale and with woolly aphid particularly, contact sprays don’t work, so I’d normally recommend that you get a systemic insecticide for those ones which is specific for those particular pests. Not the easiest of things in the world to get rid of, and persistence will be required but it’s well worth making the effort because otherwise you’ll get a serious infestation which is quite unpleasant. You can use biological control, especially if you’ve got them indoors and the infestation is in the winter, but obviously when you put them back outdoors, the biological control isn’t always successful unfortunately. As far as compost and potting up is concerned, always use a John Innes based compost for Citrus, they much prefer it. Don’t over-pot, try to pot up a little and often, so just go to one size bigger pot each time: sometimes they’ll be happy in there for a couple of years, sometimes just the one year, but just keep it ticking on, as I say, a little and often with those ones. Simple instructions, and then you’ll have a very happy Citrus.
Climbers for a seaside garden
Q. Please can you suggest some flowering creepers which are suitable for a coastal garden?
A. Some of them are common climbers like Honeysuckles, Russian Vine, roses, Hydrangea petiolaris, Wisteria solanum (which is the Potato Vine). Climbers benefit from the protection they are climbing over, which reduces the wind damage.
Climber for south-facing wall
A. Climbers would include the Honeysuckles and a fair proportion of Clematis. If you want to go for something more unusual you could consider Actinidia kolomikta, Schisandra and Campsis.
Climber for a south-west wall
Q. Please can you suggest a climber for a south-west wall?
A south-west facing wall has probably got be one of the easiest positions to cover. Most climbers would really enjoy this sort of a situation, so – almost – the sky’s the limit. A south-west facing wall – even on the coast - is quite a precious position, so don’t squander it on something too common! I would consider looking at something really out-of-the-ordinary. A few choices would include Fremontodendron ‘Californian Glory’, with wonderful, big, golden-yellow waxed cups – it’s actually a wall shrub, I suppose, rather than a climber and it has almost a figleaf-shaped leaf. If you have a skin allergy, though, be careful if you handle it, because the indumentum on the underside of the leaf comes off and it itches like merry hell on your skin and can cause irritation problems. But it is a beautiful climber: if you see it in full flower, it’s really, really striking. Another real favourite for me would certainly be Cytisus battandieri, the Pineapple Broom, partly because pineapple is my favourite fruit in the whole wide world and anything that smells or tastes of it has got to be a very good choice. Again, it’s a wall shrub: it’s got a leaf that’s very unlike normal broom in that it’s a soft, rounded leaf with very fine, grey hairs on it and like most plants that have a greyish foliage, it's very good on the coast. The flower spikes are probably nearly five or six inches tall. The individual flowers are true broom flowers, but they stand up like a little flat cone: it smells of pineapple, delicious. On a south-west facing wall it would be a gorgeous choice.
If you wanted to go for a combination planting in that position, you could think about a climbing rose, maybe with a clematis growing up through it, which would look really good. You might think about something like ‘Dublin Bay’ which is a wonderfully rich, crimson velvet-coloured rose. Through that you might possibly consider growing a clematis like ‘Nellie Moser’ or ‘Bees Jubilee’ which are beautiful soft lilac with a deep stripe in the centre of the flower, which will look really good together. Or you might go for a gold combination and possibly think about Rosa ‘Golden Showers’: I might consider putting something like Clematis Jackmanii ‘superba’ which is a dark purple clematis through it. Either of those would make a good combination. One other thing I might possibly toy with growing in a position like that would be a Campsis. Also known as Bignonias, they have lovely trumpet-like flowers and they need to be grown on a hot wall so that the wood will ripen properly andt form the flowers: it is relatively free-flowering in that position. They flower in the late summer, and if you get one when it’s fully in flower it’s really striking, really splendid.
Q. Please can you suggest some colourful foliage for all-the-year-round effect?
A. This is a huge section, but some of my favourites which suit most conditions include Photinia "Robin" which gives young red growth for virtually twelve months of the year, Aucubas (commonly called the Spotted Laurel), these are a much maligned group which thrive in poor, shady conditions, bringing a flash of light to otherwise drab areas. All the evergreen Euonymus, which range from groundcover to substantial bushes, are generally best known for their flamboyant spring colour. If you choose one of the variegated varieties "Flaming Silver" this will give you the best of both worlds. If you do have a garden in a milder area, have a look at the Coprosmas which come in a lovely range of coloured foliage which is also deeply glossy. And that's just for starters!
Comfrey, breeding true
Q. If I sow seeds from my Comfrey plants, will they breed true?
A. With Comfrey, it will depend on the variety. If it’s Symphytum officinale, which is the straight species, then it will come true from seed because that is a straight species, there’s nothing to go back from, if you like. If it’s a selected form, one of the named varieties like one of the ‘atlanticum’ varieties may be, then that will not come true from seed and again you may get variations on a form. But Symphytum, even with the named varieties, are not heavily hybridised, so even if they take a step back down the evolutionary chain, you’re not going to find a dramatic variation from the original plant with those ones. They’ll also propapagate so easily from runners: you can break pieces of them and pop them in the ground and within a couple of weeks you’ll have a fresh baby rooted and raring to go. So Symphytum is one of those plants that’s dead easy to propagate. And of course Comfrey’s a brilliant thing for a green manure crop – either put it straight into your compost or make a fairly disgusting brew by putting it into water.
Comfrey, when to move
Q. When can I move some Comfrey plants? Can I divide them, too?
Now is probably as good a time to do it as any, and probably about as late as you’ll get away with. If you’re going to move the clump intact: dig around, lift it up, dig a new site, pop it in, fill the hole back in, give it a really good soak and it probably won’t even bat an eyelid! If you want to divide it, which you’d probably still get away with now: you want to lift the clump and put two forks back-to-back within the clump and push the handles together and that should split the clump quite nicely – or you can just chop it through with a spade. Get the holes prepared, fill them with water and let it soak away. Then put the clumps in there, backfill them with soil and they’ll be fine. I’m not going to say that Comfrey is un-killable, but it’s close! It’s a very well-behaved and tolerant herb.
Q. Please can you suggest some companion planting for a vegetable patch?
Companion planting was used for many years as a natural method of pest control, both in the garden and in the vegetable garden, but became less popular with the easy availability of pesticides which made control of insects easier – or so people thought. But with the resurgence of organic gardening, people have been much more conscious of whaqt they are eating, companion planting is gaining in popularity once more. I agree a fairly obvious example are planting things like Marigolds next to carrots, because the smell of the Marigold is very strong and will override the smell of the carrot. Usually, French Marigolds are used, not English Marigolds. If you think of the very smell, whiffy Marigolds that you use for bedding – the smellier the better, basically. Tagetes will work as well in that sort of a situation. The Marigold family are probably one of the most popular plants that are used for companion planting, because of the overriding smell which masks the smell of the plant you are trying to protect. Other companion plants form almost a symbiotic relationship with the plant that you’re growing intentionally, i.e. the vegetable and the companion plant you put in, because sometimes a chemical will be released which will, again, normally fend off insects. Virtually all companion planting revolves around disguising the crop you’re growing from the predatory insect. I can’t think of any examples of companion planting that are done for disease purposes in the form of a fungicide: most of them in fact are just for pesticide control. But you can use things like Marigolds near the base of Runner Beans, they work quite nicely to disguise the smell. But when you look at some form of non-chemical gardening – I am always cautious of the use of the word ‘organic’ because I’m not sure actually of the true meaning – in non-chemical gardening there are a lot of other things, along with companion planting, that you can use to cut out chemicals from the garden, whether it’s something like the barrier method, again for carrots, where you put a small screen around them – Carrot Root Fly, believe it or not, are afraid of heights and don’t fly over eighteen inches above ground, so a little two-foot roll of fleece around your carrots will protect them. Simple tricks like that do go a long way to helping the plant.
Compost for succulents
Q. What sort of compost should I use for starting and maintaining cuttings of small succulents for rockeries?
Most rockery plants and certainly most succulents do better if they’re in a relatively low feed compost. They prefer to be in a loam-based compost, so I would normally recommend a John Innes No 1 for rooting – but do make sure you work some extra grit in with them, because they really do need to have very good drainage to do well. Alternatively, you could try rooting them in a Coir compost: we have found that we can be very successful with most species of plants, ranging from Camellias right through to succulents. It’s a very versatile medium because it’s free-draining, which allows you to add as much water as you need without encouraging the plants to get rotted. So either of those two would do particularly well.
Compost, how to make
Q. Please can you tell me how to make good compost?
A. This is always the 64-million-dollar question, and you will get almost as many answers as there are gardeners. However, my own recommendations are usually to make your own compost bin out of timber. The basic construction should give you three fixed sides with timber fixed in such a way as to allow approx one-inch gap between the boards or if you are using a single sheet, drill half-inch holes approximately every six inches. The fourth side should have the same properties but be removable for easy access to your compost. I usually recommend that you aim for a one-metre cube.
So much for the physical container, the important bit is the stuffing! The key to good compost is layering. You will almost certainly kill your compost heap if you put in more than three to four inches of grass clippings without putting a ore open layer of material inbetween, which will allow the air free access. My husband prefers to allow the grass cuttings to dry out for a day or two before putting them ion the heap, but opinions vary on this.
One of the other most important aspects of getting a good compost heap going is an activator. Now traditionally, male gardeners have easier access to a free and very effective activator, which is human urine. Of course there’s nothing to stop the ladies from doing the same, it’s just that the application is a little more tricky. If this doesn’t appeal (and don’t be put off by reasons of supposed hygiene, as uric acid breaks down very quickly), then you can buy proprietary activators such as Garotta or Ammonium Sulphate. This should be watered on as all composts need some moisture.
Finally, a square of old carpet should be put on top of your last layer and lifted off as you add more to the heap. I prefer to put a waterproof sheet over the whole lot. Once you have filled your compost bunker and tucked it up nice and warm, leave it for approximately four weeks, then open it up and turn your compost out either on to a sheet of plastic or into a second bunker next door, aiming to put the newer material from the top to the bottom of the next bunker. This can be repeated two or three times until the compost has reached a level of decay to your satisfaction. One final tip, when you empty your compost bunker to use, leave approximately six inches in the bottom of the bunker to act as a starter for your next heap. I never said it was easy!
Cordylines in polytunnel
Q. I have some Cordylines in pots in a polytunnel. Some of them have a layer of Vermiculite spread over the surface of the compost and these plants are looking very yellow. Any suggestions?
A. Cordylines are hungry feeders and will respond to almost any fertiliser but I would probably recommend a soluble balanced feed, something like Miracle-Gro. Feeding a little and often will produce good results. I think the Vermiculite is irrelevant to the issue.
Cordyline growing next to house
Q.I have a 15 foot (at least) Cordyline australis growing six feet from my bow window. Is it a threat to the house foundations – and could it be moved?
A. The answer is: not a cat-in-hell’s chance, no. It will not move and survive! It’ll move, yes, but in ‘kit form’! But the chances of it actually doing structural damage to your house, unless you are on heavy clay soil, are slim to negligible. So, unless your reasons for wanting to move it are for reasons of light, personally I would leave it where it is.
A. No, the honest answer is, they won’t shoot again. Also, Cordylines are susceptible to a disease: we don’t really know what it is, but they are dying. We think it’s a form of Phytophthera, but what’s happening is the tops are dying and the stems are going all rotten and soggy in the middle. Even if we cut them back, they’re not re-shooting, so in all honesty I would say, if it’s gone rotten and soggy in the middle, if it’s this that’s caused it – then it won’t shoot again. You’ve got two chances: you can chop it back down to ground level and it has two options – it can shoot or not shoot, you haven’t lost anything.
Cordylines, yellow marks on
Q. I have a number of Cordyline palms in pots. Every winter their leaves develop yellow blotches, although in spring the new growth is a healthy green. Could you tell me what causes these yellow markings and suggest how I can prevent it happening?
A. It's difficult to pinpoint the precise cause of yellow spotting, but generally it affects Cordylines that seem to be a little too wet at the roots. As long as the young growth comes through fine, then don't worry about it.
A. You sound as though you have an interesting garden and are not afraid to try some different plants. However, in the case of your Corylopsis, you have chosen a slightly tricky subject. It will certainly resent being moved in the depths of your cold weather and I would recommend waiting until you get a mild period during the winter to move it. However, in the mean time it would probably be a good idea to root prune it in preparation for the move. Go around the plant, just inside the canopy edge of the plant itself, with a spade and cut straight down. Do nothing else but this will sever the roots ready for the move. Corylopsis prefer a more sheltered site, semi shade is fine but they enjoy a hot autumn to ripen the wood and ensure a good flower display. If the weather hasn’t offered a suitable window before it flowers, don’t think that you have missed the boat. As long as it has not come into leaf it can still be moved.
Couch Grass, getting rid of
Q. How can I get rid of Couch Grass on my vegetable patch?
A. Couch Grass is one of the gardener’s worst nightmares. If you’re digging the garden over, and you want to do it organically, you have to have X-Ray vision because you need to take every little bit of root up. So if you want to get rid of the Couch Grass, the best way to tackle it is to dig down a fork and just loosen the soil around that area and gently pull the Couch Grass out, follow it back as far as you can, loosening the soil all the time and pull the root away; all the subsequent roots should come away with it. Continually pulling Couch Grass will eventually weaken it, but it is a job of love, you have to keep doing it. But if you’ve got Couch Grass coming up through a favourite plant, it’s the only way to do it because you can’t, obviously, spray indiscriminately with weedkiller.
If you’ve got Couch Grass coming up in an area of kitchen garden which you’re clearing, personally I would spray with a Glyphosate weedkiller while the Couch Grass is still green and growing actively. Let it take it back in because it’s a systemic weedkiller, and hopefully it’ll go down and kill the roots; and then you may find that some small pieces come up subsequently which you can deal with on an individual basis, either by digging them up or by spraying a small area individually. I would probably favour a two-pronged approach – attack it en-masse with weedkiller and then tackle each piece individually by loosening the soil and digging it up, following it back to base. Couch Grass is almost diamond-tipped, it’s a very pointed grass in the rhizome stage, so it can spear its way through anything. It’s a very invasive grass from that point of view and that’s why it just ‘points’ its way through any rooted areas, and you find it coming up through existing plants without any resistance to it at all.
Cruel Plant, what is it?
Q. What can you tell me about the Cruel Plant or Araujia sericifera? I’ve just been given some seeds.
This is a climber: it’s not very often grown. It’s a toss-up between being overrated or quite interesting! I can’t say fairer than that! It’s quite a nice evergreen climber, not very often offered at all. It grows best on a south or south-west facing wall. I wouldn’t say it’s the hardiest of climbers, but if you can get the seeds to germinate, I think it makes a nice climber to use as a foil for other things. So if you’ve got one growing you can grow something like a Clematis up through it as well. I’m trying to remember the colour of the flowers, I’ve got a sneaky suspicion they’re white, but don’t hold me to it. But it is a nice climber, it is well-worth growing. It’s salt tolerant and certainly one that I would be happy about growing in a coastal area – I wouldn’t have any concerns about that.
Ideally you should grow it on a south, south-west, or south-east facing wall. Having said that, it will actually take semi-shade if it’s got warmth, but I wouldn’t put it on a north wall – a shadey south wall would be fine. As for soil, it’s not fussy at all, as long as it’s got good drainage, it won’t take heavy, wet soil. It doesn’t mind acid or alkaline although I wouldn’t say it enjoys an excess in either direction, it’s a remarkably tolerant plant.
As for its name, ‘Cruel Plant’, I have absolutely no idea. I have a feeling that it’s got some spines on it that are hidden. I’ve got a fascination with common names and that’s one I haven’t checked up on yet.
Cultivators, for vegetable patch
Q. I am thinking of buying a mechanical cultivator for my medium-sized vegetable patch. Suggestions, please?
A. For a domestic situation, I would recommend the Mantis Tiller, which is remarkably light, weighing about 20lb. It has a strange array of attachments but as a rotovator it is small enough to use between existing plants but man enough to deal with the vegetable plot. For more information, go to www.mantis-uk.co.uk. If you go to buy a rotovator you really need to try before you buy, because some of them are distinctly unwieldy. They work on the principle of rotating blades under a guard, and most are just variations on that theme. Another word of warning: only use these when wearing protective footwear, as they have no respect for toes.
Cucumber seedlings, yellow-looking
Q. My Cucumber seedlings were grown in a seed compost in a peat pot. The first true leaves are looking a bit yellow, is that normal?
A. The initial sowing in a seed compost, that’s fine. Once they’ve been pricked out, then they should go into a stronger compost. Depending on how old they are, if the first true leaves are looking a bit yellow, it may well just mean that they now need some feed. If they’ve been grown indoors there shouldn’t have been any temperature variation, so that shouldn’t be a huge problem. So I would suggest that some gentle liquid feed will be all that they really need at the moment. Bear in mind that all the Cucurbits like a lot of food and are fairly hungry feeders. But at the moment, gently does it.
Cuttings, taking in early summer
Q. Are there any cuttings I can take at this time of year?
A. Stem cuttings from perennials and softwood cuttings from lots of tender perennials, including Fuchsias and Pelargoniums. Also softwood cuttings of some shrubs - but this is better done with semi-ripe cuttings later in the summer.
Cuttings, taken in late July
Q.Can you suggest tree and shrub cuttings which I can take now?
A. Virtually all shrubs are suitable for cutting material now, as they are best treated as semi-ripe cuttings. Tender perennials such as Fuchsias and Geraniums (Pelargoniums) will provide a wealth of cutting material now and free babies for next year. Heel cuttings are a matter of personal preference, and professionally is not a system we use very often. Most cuttings are better trimmed above the heel and below a leaf joint.
Cyclamen indoors, choosing and caring for them
Q. How do I grow Cyclamen indoors? Which varieties are best, and how do I look after them?
A. Firstly, if you’re going to grow Cyclamen indoors as a houseplant, buy them from a reputable centre. Do not be tempted to buy Cyclamen from outside garages or anywhere they’ve been left outdoors, unless it is a variety that specifically says they will tolerate being outdoors. There are some, such as the ‘Laser’ series and the ‘Miracle’ series, both of which you can actually use for bedding outside if you like, as well as using them as a houseplant. But for most Cyclamen, you can buy a nice fat one in flower, you can buy one with plenty of buds on it: but make sure it’s a good, healthy plant with a nice-looking corm which is just sitting on the surface of the soil. Once you get it home, it likes somewhere that is cool and light – not over-cold or over-hot, no extremes of anything really. And it’s vitally important to water from the bottom upwards, don’t water it from the top of the pot. Stand it in a saucer, let it drink what it wants, then let the excess drain away. Always take off flowers when they’ve finished, trim them back (you can just snap the stalks off but you’ll be left with a bit of stalk then, so personally I would recommend trimming the flower stalk right back down to the base by the rosette, but carefully.
As for compost, they are really un-fussy. Generally, the compost you buy it in would be a commercial compost and would run out of steam within a month of your buying your Cyclamen, so I would probably recommend that you start liquid-feeding it within a month or six weeks of buying your Cyclamen. If you do decide to pot it on, it won’t need doing until after it’s finished flowering, and then an ordinary multi-purpose compost is fine.
Q. The Mediterranean Cypresses – the tall, dark, pencil-shaped Cypresses – can they be grown in Cornwall?
This is a sixty-five thousand dollar question, unfortunately! Cupressus sempervirens is the Italian Pencil Cypress. Yes, it will grow in the UK and yes, it will grow in Cornwall, but what it really loathes, hates and detests are severe wet winters – and what have we just had? – a severe, wet winter. We’ve got them in at the Nursery at the moment, lovely specimen ones which have just come in to us from Italy. Fair enough, they have no problem growing them over there. But if you’re going to grow them over here, then a well-drained, sunny position – coastal garden ideally – would suit them well. They will not tolerate wet, cold, north-facing aspects, where they never really get a chance to dry out, grow out of the damage that’s been done to the root system and hopefully try and survive that, at the same time as they’re trying to grow! So I would not have said that it’s an ideal combination.
They are salt tolerant, but you really need to give them just that little extra bit of protection, that is the honest answer. They just won’t tolerate the rain – they won’t enjoy it. It’s a combination of factors – the cold north wind, the wet and the exposure – it’s just too much for them.
Cytisus battandieri, pruning of
Q. Eight years ago I planted a Cytisus battandieri, about 1m in height, against a west-facing wall of my house. It is now about 2.5m high and rather leggy. Last year it flowered profusely. I would like to know if it is possible to prune it right back to regenerate growth from the base of the plant, as it is bare to about 1.5m.
A. It doesn't enjoy hard pruning. Best method for pruning is to shorten back the wood that had flowers on, immediately after flowering, but don't prune into old wood.
Damping off in young seedlings
Q. How can I avoid or treat damping-off in young seedlings?
A. The best way to prevent your seedlings from damping-off is probably to water them with Murphy's traditional copper fungicide, but make sure you do follow the instructions. But basically water them at each stage, i.e. at seed sowing, at germination and at pricking out. Seed compost must be able to drain freely. Good air circulation is also vital, once germination has taken place. Another traditional cure for damping-off has always been Bordeaux Mixture, but really the best treatment for it is good ventilation, making sure that you are using seedtrays that have been properly washed and sterilised and to use fresh compost – not compost that you’ve had hanging around for a year – before you start sowing your seeds. So, good ventilation and correct watering will do a huge amount to prevent damping-off.
Dasylirion, choosing and caring for
Q. Can you recommend varieties of Dasylirion and suggest how I should care for them?
A. I suppose the most famous Dasylirion is the one that’s grown on the Isles of Scilly at the top of the lovely steps going towards the big statue of Neptune, which I think is probably D. glaucophyllum. But they’re all very handsome plants of the Yucca-style of family. But they always look as if the ends of the leaves have just been very gently shredded which makes them almost slightly fluffy: where a Yucca would spike you, these ones will just give you a rather nasty brushing! They actually feel and look lovely. But they do need to be grown in well-drained situations, very much similar conditions to Yuccas, in all fairness. They’re from the Dracaena family, so they like the same sort of conditions as palms, Yuccas – all those sort of things. They really do not enjoy being anywhere where they get very, very wet in the winter, so if they have high rainfall they must have good drainage. Beyond that, once they’re established they’re relatively good, tough plants, but not something I’d recommend for the top of Dartmoor! They’re definitely something that benefits from a coastal garden. But they’re wind-hardy, salt-hardy, nearly-everything-you-can-throw-at-it hardy. They’re not that good with cold, their natural habitat is Mexico – coastal areas in the top of South America, so they’re not hardy as such which is why they’re good coastal plants because there are so few frosts. They also flower, but don’t wait up for it, as it were, they don’t have a flower as lovely as a Yucca, but they do flower and they are of the same ilk.
Date Palms, slow growing
Q. We have some one-year-old date palms which we grew from stones. They're in three-inch pots and still only 6inches high: they don't seem to grow.
A. They need to be in a protected environment and they are slow to start with. Again, try a weak liquid feed every fortnight. Don't pot them on at this point.
Dierama, best place to grow
Q. What sort of conditions best suit Dierama pulcherrima? I'd like to know the best location in the garden. Does it like damp or well-drained soil, shade or full sun?
A. Dieramas like those mythical conditions of well-drained, moisture-retentive soil. Basically, they're happiest growing in sun in soil that does not get too dry but does not get waterlogged in the winter. Crack that, and you can grow your Dieramas!
Dimorphotheca (Osteospermum), wilting
Q. I see on your website that you have a "plant clinic," but I didn’t see my particular problem addressed. Can someone possibly help me with my Dimorphotheca barberae? I've had it for about a month. It was blooming when I got it, I planted it in a large container after the last bloom had finished—well-drained soil and pot. It's been getting full sun and I was concerned because it seemed to have stopped blooming after the original flowers work gone. This week I found a large bud on it, and was delighted. But yesterday I found the whole plant wilting. I poked in the soil and found it somewhat dry (but not bone-dry), so I gave it good dose of water. Today it's still badly wilted, so I took it out of the pot and examined the root ball. Looks fine. The only notable thing was an earthworm in the pot, but surely he's not doing any harm. I've repotted it and put it out of the sun for the time being.
A. It looks to me from your photographs as if it has been over-potted and over-watered. Looking at it, I think the answer is that it has been put into quite a big pot, quite early on. Despite the fact that you’ve had it on a sunny, warm patio, I think it’s just gone into too big a pot too quickly. Sometimes (not always) they can go downhill when that happens. The way it’s collapsed strikes me that the problem is at the root. If I were you I would knock it out of the pot and go down a size in pot – ‘unpot’ it, I suppose, rather than ‘repot’ it! Put it into a light multi-purpose compost, make sure it’s got very good drainage, keep it out in the sun again and don’t overwater it. You could use a John Innes compost. Make sure that the bottom of the pot has got crocks in it, it should then be fine so long as it’s got good drainage which is a key thing. And basically, cross everything...!”
Disinfecting greenhouses and pots
Q. What's the best way of disinfecting greenhouses and pots?
A. The best disinfectant, and readily available, is probably Jeyes Fluid. A good alternative is Armillatox, which is a general purpose garden cleaner: it can be used on pots, paths, greenhouses - and any passing garden gnomes.
Dried flowers, choosing plants for
Q. Please can you suggest some plants I can grow for dried flower arrangements?
A. There are some lovely plants which will dry well, and some probably more unusual than others. I would suggest the following: Alliums with their big, handsome globular seed heads, which should be cut and hung upside down in the shed in the summer; Phormiums, which produce slightly prehistoric flower spikes, again have fabulous dried seed heads; Hydrangeas dry especially well but usually when the flowers are nearly finished and the colours are at their richest; Vebena bonariensis is like purple Statice and again, cut and hang when in full flowers; and Poppies, the large oriental variety, produce classic seed heads for drying. For something slightly unusual try Agapanthus seed heads: once the seed pods have dropped, spray them silver to make fantastic decorations. You can always let nature help in the spring: look at the ground underneath large-leaved Magnolia trees, where you will often find perfectly skeletonised leaves – up to 12 inches long – try these for a different tablemat.
Drought, choosing plants to withstand
Q. Can you suggest some plants that will grow in drought conditions?
A. Quite a long list, but in general terms most succulent plants are well adapted to drought conditions. Similarly, a lot of the more aromatic plants like lavenders, thymes, rosemary etc enjoy those conditions. When it comes to trees and shrubs the minimum temperature for your garden will have more influence on your choice than dryness, surprisingly, trees like olives will happily grow in this country, especially in drier conditions - but I'm not sure I would want to try olives in deepest Scotland! Plants are often more adaptable than we realize, and once well-established will tolerate a reasonable measure of drought: but you only have to look at the plants that grow in Mediterranean countries to get more inspiration.
Duckweed, how to remove from a pondQ. How can I remove Duckweed from our fish pond?
Duckweed in ponds is one of the most pernicious weeds, and probably one of the most frustrating. The best method for removal is by physical means: personally I find the risks associated with chemicals in ponds not worth it, unless we’re talking several acres of water here. The best tool for the job is a fine mesh children’s shrimping net, or a hoop of coat-hanger wire with an old stocking threaded through it and the ends of the wire pushed into a bamboo cane. And then all you require is time and patience, and – depressingly – some days there will seems to be more than there was yesterday. But be persistent, spend five minutes or so every day, and it becomes quite therapeutic, in addition you will eventually win.
Echium pininana is undoubtedly the most popular, but you have to remember that the Echium family includes our native Bugloss. However, if you want other varieties that offer something similar to Echium pininana, then Echium candicans (fastuosum) has a RHS Award of Garden Merit, and is a nice dumpy form. Echium x scilloniense is a hybrid from Tresco, midway between the two. Echium pininana ‘Pink Fountain’ is a softer coloured but quite tall variety to ring the changes, and it’s worth remembering that all Echiums make good coastal plants.
Echiums, sudden wilting of young plants
Q. Why do young Echiums sometimes wilt suddenly and die?
A. Generally they're affected by a soil borne fungal infection, which is one of life's little irritations which we have to put up with. Try drenching with a general purpose fungicide. They tend to use mycorrhizal soil organisms and will generally do better when self-seeded from parents into soil than when you try lovingly to grow them in compost.
Eucalyptus, choice for small garden
Q. Please can you recommend a Eucalyptus variety for a smallish garden.
A. The best variety will probably be Eucalyptus nicholsii, which has small fine foliage and is much less vigorous than most, but bear in mind that all Eucalyptus are very tolerant of pollarding and you can maintain most varieties as a shrub by pruning hard every February, and that will encourage juvenile growth (in my opinion, the best bit of the tree). For the real Eucalyptus enthusiast, if you're ever in Wales, you may just want to visit the National Exhibition at Celyn Vale Eucalyptus Nurseries at Merioneth. Tel. 01490 430671.
Eucalyptus, cutting back
Q. We have a Eucalyptus tree which is now beginning to get in the way. Can I saw off one of its branches now (in May), or should I do it at another time of year?
A. Yes, do it now!
Eucalyptus, do they undermine?
Q. Is it true that a Eucalyptus tree can undermine a house?
The whole question of subsidence caused by trees strikes fear into the heart of every insurance company in the country. As a rough guide, unless you are on heavy clay soil, subsidence is unlikely to be a major issue. However, common sense dictates that you do not plant a large, vigorous tree five or six feet from your house, as the roots have to go somewhere! In the case of Eucalyptus, if you are planning to let it attain its natural height, I would not consider planting it within 20feet of a building. There are plenty of smaller and less vigorous trees which can be planted nearer the house.
Eucalyptus, keeps growing Q. We have a Eucalyptus. It’s 30 feet high, it’s next to the house and has been growing there for about fifteen years. We don’t know which variety it is, but when do you think it’s going to stop? What’s it doing under the house?
A. As far as the Eucalyptus is concerned, the sky’s the limit. And as my old boss used to say, ‘Plenty of room upwards, gal.’ They will keep going! For most Eucalyptus, if they’re ones like gunnii or niphophila which are the most commonly grown ones, growing to 80 feet (24m) is not out of the question. Now obviously they do make a substantial root system to support that and, if it is too close to the house, you do have a risk.
You don’t normally have a risk of subsidence unless you’re on heavy clay – the subsidence then is caused by the roots of the tree sucking all the moisture out of the soil, the soil shrinking – your house dropping. But what more often will happen down here is that the bulk of the roots become such that it can literally forge its way through something and crack it apart, so rather than causing subsidence, it causes – I don’t know what the opposite of ‘subsidence’ is? ‘\ Upsidence’? But it can push things apart and cause walls to crack, that sort of thing, it can cause paving to be pushed up, rather as if there’s a small volcano moving around underneath. Yes, that is an attendant risk.
If it is too close to the house, then one solution would be to pollard it every couple of years. If you don’t want to get rid of the tree, you like the foliage but you don’t want it to get any bigger, keep it down to something around ten or fifteen feet. The root system won’t grow bigger because it doesn’t need to. Root systems only grow as big as they need, to support the tree above. So you can curb its enthusiasm that way.
But if you let it go, you’re going to have almost as much underground as you have above ground. Something to bear in mind: that’s why I never recommend Eucalyptus as a wall shrub! It won’t be stopping at 30 feet!
Fasciation, causes of
Q. What is 'fasciation', and does it matter?
A. Fasciation is when you have two or more stems fused together. It usually happens with flower spikes and can produce some quite surreal flower effects. It is normally caused by nutrient imbalance or sometimes just the weather, but it occurs in the wild and is not a manmade problem. If you want to chop it off, fine. But if you want to watch it being weird, do so!
Fascicularia bicolor, description
Q. What is the name of the succulent which grows on the banks around the Lodge at the Loe Bar? It grows in large rosettes of long thin leaves with backward facing spikes. What is striking is its bright red centre.
A. I haven't been there, but this sounds like Fascicularia bicolor. It's only seen in coastal areas, usually in the west country. In fact, it's now indigenous in coastal areas in Cornwall and on the Isles of Scilly.
Fatsia japonica losing growing tip
Q. I have a Fatsia japonica which has lost its growing tip. What happens next?
In my own opinion, Fatsias are much better if they do lose that central tip, because it does encourage them to bush out. It does mean, however, that you’re going to end up with a very, very fat plant, because again it’s the nature of the beast with Fatsias. But it’s very rare for you to get one that continues to grow for very long with one leading tip: virtually always they will, one way or another, lose that growing tip and it will then shoot out and be multi-centred. But what I would suggest is that if the growing tip has gone, depending on how tall the Fatsia is, I would be tempted to have a look at it: if it’s over two foot tall and it’s only the tip of the growing bit that’s gone, I would prune it back down to around the two foot mark or maybe just under, and then that would encourage it to shoot out from lower down and make a more evenly bushy plant. If it starts shooting above two foot, you end up with a sort of half-standard effect which can look rather weird! So if it is the tip gone, then I would look at giving it a deliberate pruning.
Q. Please can you suggest some fragrant plants for people with visual impairments?
A. Fragrance is a matter of personal taste, and what some people think smells nice, others may turn their noses up at. So for what it's worth, this is my list. Virtually all culinary herbs will provide a lovely aromatic flavour to your garden and indeed to your cooking. Roses are an obvious choice, but bear in mind that some modern varieties are not that well scented, so it's often better to choose a rose when it's in flower. Other aromatic shrubs for foliage include lavenders, Santolinas and Lippia. Cistus will give off a very Mediterranean aroma in hot and sunny wather. For flowers there's a huge choice, but some of my favourites include Viburnum, Clematis (particularly the montanas), honeysuckles and - surprisingly - Berberis. Hopefully this will be enough to make a start.
Fruit, taking hardwood cuttings of
Q. Is it possible (in late February) to take hardwood cuttings of Gooseberry and Black Currant?
A. Yes, it is. With hardwood cuttings, you can really carry on taking them pretty much until the new leaves come and the new growth starts. So there’s no reason not to take hardwood cuttings now and get yourself some little freebies growing along nicely.
Q. I am thinking of growing a Fuchsia hedge. How hardy are they? How do I propagate them?
A. Fuchsia hedges are an excellent choice and are reliably hardy in most coastal areas, however, if you lived on the top of Snowdonia there might be a problem! Varieties to choose would include Fuchsia magellanica and most of the F. magellanica varieties. Fuchsia 'Riccartonii' will also make hedges between five and eight feet high and which flower for months and months. Cuttings are very easy, take and treat as any other Fuchsia - in other words, take softwood cuttings in spring or summer.
Fungus, in compost
Q. There is a grey, fluffy fungus in the compost of the plant pots outside. What is it, and will it harm the plant?
A.If it’s a micorrhizal fungi, then that would be almost white, I suppose it is fairly fluffy – it’s like a bloom. It’s something that’s growing in a sort of symbiotic relationship with the root system. What it does in effect is to help the plant access nutrients from the soil and it will inoculate against diseases and infections. You can in fact buy micorrhizal fungi to use for that purpose, particularly when soils have been exhausted or you may have replanting. problems, they’re well worth using. So it’s possible that it may be that.Particularly with conifers you will find they produce their own micorrhizal fungi very quickly, which inoculates the compost in the pot. If you buy one, and you knock it out of the pot, you'll think ‘Oh, what’s all this white fluffiness?’ It’s good stuff, you certainly don’t want to get rid of it. Any other fungi that you find growing in the body of the compost, it’s very rare that it’s anything that’s going to be a problem: it may be something that’s come from the com post itself, it may be something that’s washed in, but soil is a living organism in itself, whether it’s artificial compost that you’ve bought as opposed to your garden soil they have lives of their own and ‘doddies' living within them and it’s very rare that that sort of thing could be an issue – you’re more likely to have a problem if there are pests in there rather than diseases. So I would say, on the whole, not a problem.
Furcraeas out of doors
Q. Can you grow Furcraeas out of doors?
Oh yes, very definitely. In fact, if you go to quite a few coastal places, you’ll see Furcraeas growing extremely successfully out of doors – the Isles of Scilly, where they almost attain weed-like status – the little bulbils that form on the flower heads will take root very easily. They’re not very frost-hardy. At the nursery, we tend to overwinter them in an unheated tunnel and they come through remarkably well. Bear in mind that this winter we went down to about -8°C, so they’ll take a reasonable amount of cold, so long as they’re dry. What they won’t tolerate is wet cold, like so many plants unfortunately. But yes, very successful in frost-free coastal conditions – very happy bunnies, seem to take just about anything that the weather can throw at them in that situation. And of course they’re such a wonderful architectural plant to have anyway. They don’t like it if it’s too 'cold cold' – but they’ll take the south-westerlies, the prevailing winds, the coastal conditions quite happily. I’ve seen fifteen-foot specimens on St Mary’s and Tresco – they’re quite fantastic, really impressive.
Geraniums from seed
Q. Please can you suggest some varieties of Geraniums (the Cranesbill sort, not Pelargoniums) to grow from seed in exposed conditions in West Penwith?
A. This depends on what's available. Most of these will do very well in an exposed situation. I would recommend having a look at a good seed catalogue for a wide range. Varieties of Geranium cantabriense or endressii would be good to start with.
Geranium maderense, how to grow
Q. Can you tell me how to grow Geranium maderense?
Geranium maderense, the same as with Geranium palmatum, over in this country where we do tend to get a higher rainfall are not the longest-lived plants in the world. They like to be grown in a relatively open position, more sun than shade, reasonably good drainage – not somewhere that gets waterlogged in the winter. After that, quite unfussy, they’ll take a fair bit of wind, they’ll grow on the coast and they’re very, very free-flowering. G. madarense has the finer cut foliage rather than G. palmatum. With both of them the flowers come up in sort of panicles above foliage and the whole of the top of the plant is like a dome of flowers and which goes on for months and months in the garden. It's a very beautiful plant. As for how long they live, it depends on the soil conditions. I would normally expect to get five years out of one, at least, it may well go on for longer. It will set seed if it’s happy, so you’ll have lots of babies coming on.
Geranium maderense, rotting
Q. Why do some of my Geranium maderense suddenly rot and die?
This is probably caused by the bad winter conditions, such as we’ve had this year. Even in a mild, coastal area it has still been very cold and wet for periods of time. I wouldn’t say it’s been a very wet winter, but any cold wet weather doesn’t suit them well. Strangely enough, if the plant’s been in a pot it can get heavily waterlogged without there being the capillary action of the soil to take the excess moisture away. Also, the frost can get right around the roots, which it can’t if the plant is in the ground. So I wouldn’t be very surprised if Geranium maderense grown outdoors in containers did not survive the winter – particularly the winter we’ve just had. There’s no one thing you can pin it down to, apart from weather, but it is a combination of the wet and the cold that I’m afraid has ‘done for’ them. But hopefully, if you’ve got some survivors and if they flower you can start some more off from seed and have some wonderful babies popping around the joint. But on the whole I’d say they’re happier in the ground. If they’re in a pot, I recommend that they go into a cold greenhouse or conservatory for the winter. Don’t remove the old leaf stems unless they’ve gone brown.
Gifts, practical, for gardeners
Q. Please can you suggest some practical gifts for gardeners?
A. If you’re stuck for a present for the gardener in your life, you’ve got several choices of direction. This week, we’ll look at practical presents. Depending on your budget, I’ve yet to find a gardener who would not appreciate a good stainless steel spade (or spade and fork), all nice and shiny with a big red ribbon on. Bear in mind, if you’re buying for a lady gardener, I personally find a border spade and fork better, and if your garden is very small, a border fork and spade fit in amongst the other plants more easily. But the guys like the big ones: I think it would be better if I don’t comment any further!
Another present which is always extremely well received is a really good pair of secateurs, and I have no hesitation in recommending the Felco range of secateurs, and my choice is always the Felco No 2, which I suppose I would class as professional secateurs – basic, unfrilly, very good – and I’ve had mine for over 20 years. And you can also, if you’re feeling flush, buy a proper leather holster to go with them. Luckily they do have bright red handles, so they’re not so easy to lose in the compost heap. At the lower end of budgeting, Burgeon & Ball do a lovely range of practical gardening gifts, ranging from very nice hand tools at around £10 a time, down to the dinkiest little oil can you’ve ever seen. It looks like a half circle with a long, pointy spout on it. You buy with it a very small can of proper white tool oil. You dip the pointy bit in and you press the button in the bottom of this middle round thing down so that it sucks some oil up into the nozzle and fills it. Press the bottom of the round part of the oil can and it just drips it out a drip at a time. It’s perfect for keeping all your hand tools in absolutely tip-top condition. Brilliant stuff.
Ginger, how to grow
Q.Can I grow Ginger for culinary use, and if so, how?
A. True Ginger is not frost-hardy in this country, but given the change in climate I would say that the areas it can be grown are increasing daily! Buy some fresh ginger root at your local fruit and veg shop, making sure it is plump and firm. Pot it up as you would a Dahlia tuber. You can then have your own source of the king of medicine. In effect, treat it like a Dahlia, protecting it from winter frosts.
Globe Artichokes, how to grow them
Q. How do you grow Globe Artichokes?
A. If you want them for eating, you should get them from a specialist supplier. You can usually find these in the back of the better gardening magazaines. As far as cultivation is concerned, they enjoy a fairly rich soil with good drainage. They do dislike excessive winter wet - but then, who doesn't? If you have a windy garden, I would recommend staking the flower spike as it starts to grow. The flower heads are very heavy, and if you fancy leaving a few on the plant, they are fantastically ornamental.
Grass, growing in perennial
Q. Have you any hints for removing grass from established clumps of perennials?
Quite tricky. It depends what sort of grass. If it’s Couch Grass, then you do have a bit of a problem on your hands because you’re trying to pull out a plant that is naturally invasive and seems to make a beeline for established clumps of things. If it’s annual or just ordinary perennial Rye Grass, you can just pull it out – in fact this time of year is a very good time to do it because perennials have only just started to shoot. If there’s enough of a handful of grass there, give it a good tug and a bit of enthusiasm with a fork underneath, you can very often lift the whole thing out and it will come away quite easily. If it’s an established clump but it’s something that wouldn’t object to being lifted, it may be that you can kill two birds with one stone and actually lift and divide your clump of perennials, replant it as a bigger clump but also at the same time remove any weed or grass or anything that is near the top of the clump – because most grasses are surface rooting (with the exception of Couch Grass) and you can deal with them that way.
If Couch Grass is a major problem, then personally I would probably recommend careful – and I mean the word, careful – application of weedkiller, something like Roundup or any glyphosate-based weedkiller. It needs to be applied very carefully just to the foliage of the grass, making sure that you miss the foliage of the actual perennial itself because it’s a systemic weedkiller and it’s one of the few ways that you will actually deal with Couch Grass, which is one of the worst things a garden can get!
Grasses, choosing ornamental
Q. Please recommend some ornamental grasses for planting in an exposed garden.
A. Grasses are a very versatile group and most are adaptable and suitable for exposed situations. However, if it's dry as well as exposed, then you may need to be a little more selective. Stipas, Festuca and Hakenechloa will all tolerate drier conditions, while Carex, Miscanthus and Panicum will all do better in a moister soil. There are many gorgeous varieties to choose from, from six inches to 10ft, and something for every situation.
Q. Please can you give me some advice about how to heat my greenhouse?
A. There are a lot of heaters available, depending on your budget, and the decision should be influenced by the type of structure which you are heating. For a small, domestic greenhouse, without electricity, I would probably recommend a small gas fire, but you must ensure that you buy it from a reputable dealer. With careful use the small bottles of butane will last quite a while, unless of course you're heating the equivalent of the Eden Project. If you have electricity then a small, electrically powered heater is neat and tidy, but you do need to keep it out of the water. Once you start thinking about tunnels and semi-professional greenhouses then you are looking at commercial heaters, either gas or oil fired. In all instances I would warn against buying secondhand, unless you happen to have a tame engineer. It simply isn't worth the risk.
Q. What plants can I use for a green manure, when do you sow them and when do you dig them in?
A. Green manuring is a fantasic method of getting organic matter back into the soil and also improving the general health of your soil. The actual plant that you use will depend on the area that you are looking at treating. If, as we do at the nursery, you have to do several acres, then you need something cheap and cheerful, maybe like turnip tops or mustard, which is cheap and easily spread. It comes up and makes a good crop and is easy to rotovate back in. If you’re doing it in a garden situation, you can still use those things but they may not be the most appropriate thing to use: mustard is easy but you can buy a variety of different green manure crops to grow if you like which are specifically grown. A very good source of seed for those would probably be Chiltern’s Seeds; and from memory I think the website is www.chilternseeds.co.uk; and theirs is a fascinating seed catalogue anyway – hours of harmless fun for bedtime reading. So that would be one good source: I know that they list several different green manure crops, from grasses through to vegetable crops.
One of the nicest things you can grow in the garden – it’s not strictly green manuring in that you’re not going to plough it in – but for compost and fertiliser, there is of course comfrey, which you can grow, cut and use to make a liquid fertiliser, dig into the compost heap or dig it into the garden. Either way, it provides a fantastic source of food for your soil and works extremely well.
I suppose, if I was going to start off with a green manure crop, then I would probably look at something like mustard and cress – something easy, cheap and cheerful: try it, dig it because some of them get a bit stringy and tough and when it comes to digging them in it can be a bit of a struggle. But after that, you can experiment and see which ones suit your soil, suit your style of cultivation, see what fits in. You would normally sow a green manure crop in around April or May and you’d look at digging them in later summer to early autumn. Now, depending on what you’re growing, say for argument’s sake you had a vegetable plot and you’d cleared your winter vegetables, you would sow early, get the crop up early, and dig it in early, then look at rotation. If it was for a crop that had finished for mid-summer, you can still look at a late sowing of a green manure crop and even possibly leave it in during the winter and plough it back in in the spring and then sow in the spring. They’re very versatile, very amenable in fact to planting any time throughout the year, especially down here where it’s so mild.
Griselinia, yellow spots on leaves
Q. What is causing yellow markings on Griselinia foliage?
Markings on Griselinia foliage is probably caused by one of two reasons. One is the weather and it would just be seasonal wear-and-tear. More likely, it is stress: this could be food-related, it could be root run related, but it’s normally an indication that the plant is suffering a lack of something. If the foliage is looking yellowy I would say the plant is quite hungry. If it’s looking quite lush and green apart from the spotting on the older foliage, then I would say it might just be seasonal weather damage and nothing too much to worry about. But if it’s looking overall pinched and horrible then it needs feeding. If it’s in a pot it needs to get out in the ground, if it’s in the ground it needs a dose of general purpose fertiliser – try giving it a liquid feed which will give it a boost now.
Gunnera, how to control
Q. Is it possible to grow Gunnera and control its size?
A. Gunnera is a very popular plant but in all fairness a bit of a thug. However, what few people realise is that there are three species available of very differing sizes. The largest and most commonly seen is Gunnera manicata, but if you want to achieve this effect in a pot, without taking over the world, then try Gunnera tinctoria which usually grows four to five feet tall, still not a baby but more manageable. Just out of interest, at the other end of the spectrum you will find Gunnera magellanica which grows approximately two inches tall and makes fabulous groundcover. So you ‘pays yer money and yer takes yer choice’! But I would recommend Gunnera tinctoria as a reasonably compact plant for a pot.
Q. Do some hedging plants (e.g. Sycamore, Leylandii or Privet) poison the soil?
A. Poisoning the ground is probably too strong a phrase, what these plants do is to smother the ground and rob it of all available nutrients. They're generally very vigorous plants and, in the case of conifers, when they drop their needles these form an almost impenetrable carpet which takes much longer to break down than, for example, Beech leaves. Some conifers will also make the soil very acid, which is hostile to many other plants, and this may be where the idea of poison stems from.
Hedging, choosing species
Q. Please can you suggest some species for windbreak hedging?
A. There are two choices in terms of plant group - either evergreens or deciduous. With evergreens, if you wish to avoid the much-maligned Leylandii, you could consider Prunus laurocerasus - Common Laurel. Or for something a little more classy, Prunus lusitanica, which is Portuguese Laurel. Both of thse would be idedal for big-screening hedges. Then Elaeagnus x ebbingii makes an excellent well-clipped hedge with sweetly scented flowers in the autumn. Fuchsias make a good chlice, especially in a coastal situation, providing a very quick screen.
In the deciduous camp, there's a huge range available and much will depend on the height that you wish to maintain the hedge at ultimately. But for a quick effect, look at Alnus (Alder), Populus (Poplar) and Salix (Willow). I could go on and on but hopefully these will give you a few pointers.
Hedging, choosing frost resistant species
Q. Are Escallonia and Griselinia frost tolerant?
A. The honest answer has to be, no. They’re not as frost-resistant as other hedging plants, but, if you live in a coastal area, yes there is always the risk that we’re going to get frost when we get another severe winter, but what do we live our lives for? Should we worry about the risks all the time? Or do we get on and just think, ‘Yep, that’s another one that we put down to experience’? Personally, I think in a coastal situation it’s far better to go with what grows there. Accept the fact that not everything is going to survive every winter: it just doesn’t work like that, unfortunately. Then, when you do get a problem, if you do get a severe winter and something occurs, yup, there are going to be problems – you have to accept the good with the bad in a coastal garden, which is just the way it goes.
As for varieties, if I was going to choose a variety for a coastal situation, without doubt I would go for E. macrantha, the big-leaved pink one. But also try mixing E. iveyii in with it, which is a lovely white one, good glossy leaf with a slight crinkle, the prettiest of the white ones I think, looks really good. If I had to look at other hedging plants for a coastal situation, Griselinia is very good, yes, but I prefer Euonymus japonicus, gives you a lovely berry display on it as well if you have a male and a female: very tough – I’ve seen it hanging off the edge of cliffs and barely batting an eyelid! – and I think it makes a really, really good hedging plant. Where Griselinia has a tendency to go running up the hill and leave you with a slightly ‘bald bottom’, the Euonymus always gives you a good, dense, bushy tree right to its base.
Hedges, choosing for a flowering hedge
Q. Can you suggest some flowering shrubs for a mixed hedge? It needs to be salt-tolerant.
. Flowering plants for a coastal hedge? There’s actually a good range of plants available to you. Starting off with some of the deciduous plants, then obviously there’s the Prunus spinosas – the Blackthorn, which is the earliest white flowering hedgerow tree that you see. That could then by followed by the Crataegus monogyna, the Hawthorn or May blossom. Those are the ones that are flowering at this time of year (May and early June), and they’re the ones that really smell gorgeous. A lot of people get confused between the Blackthorn and the Quickthorn (or Hawthorn) as to what it is, and the real difference is that one being a Prunus spinosa (Blackthorn) that one will bear fruit which is related to the plum or cherry: in fact what you get on the Prunus spinosa is the Sloe (very nice for making Sloe Gin, I should add!) whereas the fruit on the Crataegus monogyna are haws and they’re rather like a rosehip and indeed are members of the same family. But also after that you could add Viburnum opulus (the Guelder Rose), in flower now in the hedgerows. You can also add Sorbus aucuparia (the Rowan), they’re beautiful flowering and are later in the year.
Herbs, choosing 12 for a new garden
Q. Can you suggest a dozen herbs for a new herb garden?
A.For this answer I’ll assume that the herb garden will be in the ground and obviously this will be “my take” on good herbs. If you actually think about the range of herbs you use for cooking it’s only approximately half a dozen – and the rest will be slightly more ornamental and/or medicinal. So these are my recommendations: Rosemary, Thymus officinalis, Sage, Salvia officinalis, Chives, Basil and Oregano. I’ve missed out probably the most common herb which is Mint, because unless you want to have a whole garden of it I would recommend growing it in a pot.
For the other half dozen herbs I would choose Bronze Fennel, Lemon Balm, Lemon Thyme, Welsh Onions, Artemesia (Lad’s Love) and Pineapple Mint – but that comes with the same caveat as ordinary Mint. And on the subject of Mint, the Mint for Mint Sauce is Garden Mint (Mentha spicata): but the reason I chose Pineapple Mint is because it’s gorgeous in a fresh cocktail.
Hideaway, how to design one Q. I would like to make a 'hideaway' in my garden - a quiet, hidden area where I can sit peacefully.
A. Hideaways have for a long time been the reserve of children, and I really don't know why. Most of the adults I know would really appreciate that little bit of private space - and where better than to put it in the garden? The first essential is a visual block from the main part of the garden or house. You can use something man-made, like a trellis, or a plant that will quickly give you privacy, like bamboo, Elaeagnus or any hedging plant. You need to decide how big a space you want to create and then mark the boundaries out accordingly. But choose your position carefully so that you don't block all the sun from your chosen spot. To that end, think about the times you are most likely to use your hideaway, if it's after work then find a west-facing nook to create your spot. Another important factor is perfume, so you might think about slabs or stones for the ground surface, interplanted with low-growing herbs. But don't be tempted by roses unless you happen to like getting prickled. One final tip, if you plant your barrier in such a way that you need to push through plants to get to it, you get two effects: firstly, if it has rained you're less likely to use your hideaway as you'll get wet going to it, and secondly a carefully positioned windchime will alert you to unexpected visitors.
Holiday destinations for coastal gardeners
Q. Can you suggest some interesting holiday destinations for coastal gardeners?
A. South-western Ireland has a wealth of really beautiful coastal gardens, set in fairly fabulous scenery. And on the Continent, my choice would be the north-west of France. If, however, you were feeling a little more ambitious, then North America - particularly around San FranciscoBay, offers not only gardens but some spectacular examples of how Nature adapts to a relatively hostile environment. The more exotic holiday destinations do palm trees very well but are best visited for their sunbathing attributes than their gardens. Generally, temperate countries have a far greater wealth of plants to be enjoyed by real gardeners.
Q. What's the best way to propagate holly?
A. Propagate holly with semi-ripe cuttings in July to August. It's quite a slow one to root and will probably take 6 to 9 months. Always use rooting powder or gel - and make sure it's fresh!
Honey Fungus, how to treat
Q.What is Honey Fungus? How do I recognise it, and what can I do about it?
A. ’Honey Fungus’ is one of those frightening phrases that have people thinking their garden is full of infections. There are three main symptoms: the most common of these are the honey-coloured toadstools which have a distinctive white ring on the stem. They will normally be found growing near the base of a dead tree or shrub. You will also recognise it by sheets of white mycelium which grow under the bark. It also produces rhizomorphs which resemble black bootlaces, however these can be difficult to spot and so should not be relied upon. There are several forms of Armillaria in the UK, but only two of these are believed to pose a risk to healthy plants. Plants that are under stress, or are weak for whatever reason, are obviously much more susceptible to infection. The disease is spread by spore production, generally moved around gardens in compost. There are no approved chemical treatments but there are some promising results coming fro the use of mycorrhizal fungi, which help to protect trees by boosting their natural resistance to disease. The most important thing to remember when removing a diseased plant is either to ensure the complete removal of the root system or, if this cannot be done, to treat the stump with an approved stump killer such as “Rootout”. When replanting in known infected areas, there are some plants which have shown themselves to be more resistance to the disease: this list is available on theRHS website.
Horse manure, how to make a liquid feed from
Q. Is it possible to make a liquid feed from horse manure?
A. Yes! Oh yes, it’s very possible. In fact my father used to do it! I can give you his recipe. He used to live in a coomb just outside Liskeard, and the wild ponies from the moorland used to come down into the coomb, in winter particularly. You could hear them coming down the road from a fair distance: the sound of the horses was followed fairly quickly by the clang of the buckets and shovel as my father used to go hurtling out to pick up their calling-cards that they used to leave as they were going off down the road. He had a big water barrel that he kept in the garden; what he used to do was to get the horse muck and toss it into the water butt. The water butt was raised up on blocks, so you could get a water can underneath the tap at the bottom. And he tossed the horse muck in there in the winter and then when he wanted to start liquid feeding in the spring, he would draw off the liquid at the bottom. And it was strong because he ended up putting quite a lot of horse muck in there. In all sensibleness, if you had a 100 litre water butt, like an ordinary, average rain butt, you wouldn’t want to put more than about probably half-a-dozen buckets of horse manure in there: that would be plenty enough for a season and then it would be hosed with water. You could just stir it around occasionally, but I generally wouldn’t recommend leaning over it while you stir it, because the smell is a little on the pungent side! But what you want to do then is draw it off – you’d probably use it on a dilution rate of about one in 20 with your water and you would feed anything with it. My father used to grow Begonias and Fuschias like you have never seen! It was the most wonderful liquid fertiliser, but as I say: as long as you didn’t mind your nose being slightly offended, your plants certainly wouldn’t be at all offended. And when you were drawing it off, you could top it up with more water and just add a bit more horse manure if it happened to become available. It’s really an ‘on-growing’ problem, if you like. Excellent stuff, works very well and you can – if you don’t happen to have a friendly horse – do it with comfrey as well in exactly the same manner. You can feed absolutely anything with it, including ericaceous plants, because once you put it into the water, in effect it neutralises any pH problems. You haven’t really got an issue with it: you can feed anything with it – I mean possibly I wouldn’t recommend it for babies – but…!
Horse Radish, how to grow
Q. Is Horse Radish wild or is it cultivated? And how can I grow it for sauce?
Horse Radish is a wild plant in this country – but you try finding and identifying it! It’s not something most people would be able to readily identify and of course it’s the root that is used for Horse Radish Sauce, so again it’s not readily identifiable by smell or anything of that nature. But any good nursery will have Horse Radish for sale during the late spring and summer when they get their mainstream herbs in. You can buy Horse Radish quite easily.
It grows nicely in the garden: it is a perennial, but don’t expect it to be the most beautiful-looking thing in your garden! So maybe it’s something that you’d want to grow in your vegetable patch, just the same as you would your rhubarb. Then you can lift it and take sections of the root off and use that for making your Horse Radish Sauce. I’ve never yet seen cloves of cultivated Horse Radish: it’s possible that there may be, but I think most Horse Radish is raised from seeds that have been collected from cultivated plants nowadays. But yes, Horse Radish is a native plant in this country.
Hydrangeas, too late to prune?
Q. Is it too late (early May) to prune Hydrangeas?
A. Oh no-no-no! Very definitely not too late. Depending where you are, it’s a very late season and yes, they have started into growth but I wouldn’t hesitate at all about pruning a Hydrangea now. An awful lot of people haven’t done their dead-heading, so you could definitely go out and do either the dead-heading, tidying-up sort of pruning or, if it’s necessary, do some more comprehensive pruning. I would have no qualms at all about doing it now.
Hydrangeas, choice and care of
Q. Please can you tell me about Hydrangea varieties and how to care for them?
A. Hydrangeas are one of those plants with a very Cornish flavour to them, and they are very easy to grow. They enjoy our mild climate, putting on vigorous, lush growth and flowering freely. The biggest mistake that most people make with Hydrangeas is to inadvertently prune off most of the flowering shoots in the spring. You should really just thin out the weaker shoots to encourage better flower size. There are numerous myths surrounding Hydrangea colouring: in a nutshell, the only Hydrangea colour is white, all other varieties have two colour spectrums depending on the soil. Pink and red Hydrangeas will appear from lime soils, whilst blue and purple will generally be found on acid- or mineral-rich soil. You do not need to plant your Hydrangeas on top of an old iron bedstead to get a good flower! You can buy Hydrangea colourant, which is aluminium sulphate, and this should be applied annually. As far as good varieties are concerned, all the 'Teller' series are excellent: 'King George' and 'Merville sanguine' will give gloriously deep colours, and the 'Serrata' varieties give smaller more delicate flowers. But there is a wealth of varieties to choose from.
Q. How and when do I prune my Hydrangeas?
Pruning Hydrangeas can be a bit tricky, but I would say that at the moment (mid January) it’s much too early to do it. I prefer to prune Hydrangeas when the new buds are starting to break and you’ve got a hint of green all over it, because the old Hydrangea heads will have been providing frost protection up until that point. So I’m usually looking at some time in March before pruning the Hydrangeas. I would certainly recommend that it’s done: if only just to tidy up the old flowerheads, it would be well worth it and it’s an ideal time to do it. But if you’re looking at young plants, you can prune them back quite hard. For a more mature plant then really you’re looking at just trimming off the old flowerheads, tidying up the bush and letting it carry on and do its thing.
Hydrangea macrophylla varieties usually flower on second year wood, so pruning is best done in spring when you can see the new growth starting, and preferably when the risk of frost is past (although you might have to be a clairvoyant to get that right), and then prune back to fat buds on last year's growth.
Irrigation in greenhouse
Q. Please can you tell me about irrigation systems for greenhouses, particularly for use in the summer holidays when we're away.
A. What you actually use your greenhouse for, will dictate the level of sophistication you need. For a propagation bench you would need a super-duper electronically controlled system to regularly mist cuttings, however, unless you have got a lot of money to play with, it's not something for the average amateur gardener. However, if you're looking at tomatoes, cucumbers and larger plants growing in the greenhouse, then you can buy some fairly simple drip irrigation systems which operate on a timer. These are very effective and water use is economical. But there is no replacement for a willing neighbour.
Ivy, on trees
Q. Does ivy harm trees?
A. 'Yes and no’ is the honest answer to this one. Ivy can harm trees if it becomes too heavy for the tree and starts to swamp it. Ivy is a self-training plant and it puts out aerial roots which will attach to the tree to help it grow up the bark. But it doesn’t actually take very much out of the tree, with its tiny roots if anything it might take some moisture which is absorbed by the bark. It doesn’t affect the health of the tree per se. The biggest risk to the tree is if it becomes so top-heavy, or if it gets up into the main branches, it is then physically swamping the branches of the tree – not the trunk – then it can become a serious problem. So you really need to weigh up the balance between the good that the ivy does, by providing more habitat for wildlife, particularly on a deciduous tree, and the harm that it’s doing if it starts to get up into the branches; if you can just get in and prune out the ivy that’s going up into the branches, you can chop it off. If at any time you decide it’s getting too big for its boots, chop off the main stem near ground level and the ivy will die. Twelve months later you can just pull it off. Shading is not the problem: ivy doesn’t often grow above the canopy of the leaves, it’s more that the weight on the branches will cause them to fall down
Japanese Knotweed, how to get rid of
Q. How do I get rid of Japanese Knotweed?
A. Japanese Knotweed is a pernicious weed and the method for control is quite simple. Do not cut it back or dig it up because it will defeat you in this way. What you must do is wait until July/August time, when it's in full flower, and then spray it with a glyphosate-based weedkiller (e.g. Roundup). You will probably need to repeat this over at least two seasons but eventually it will go. Patience is a virtue here.
Kiwi fruit, how to grow
Q. How do you grow Kiwi fruit?
A. The answer is – very easily. It’s more of a problem how not to grow Kiwi Fruit, as they’re rather enthusiastic doers. If you decide you want to grow Kiwi for the fruit, then go to a local centre that does a reasonable array of fruit. You’ve got two options open to you: you can either buy a male and a female and they will be named varieties like ‘Hayward’ and ‘Tomuri’; or you can now buy self-fertile varieties like ‘Solo’ which will do it all on their own. What you need to provide is a good amount of room: an average Kiwi plant will certainly grow at least 15 to 20 feet long so you do need to make sure you’ve got plenty of space for it! If you’ve got a male and female, then plant them together so they basically grow together and you’ve got pollination of the flowers right next to each other. For a self-fertile variety, plant it so that it can grow up and get a good distribution across any framework. I’ve grown good Kiwi fruit in a pergola which was built against the house.
You can grow them over a shed – you can basically grow them anywhere that you could grow any climber, but you need to give them a good warm position to make sure that the fruit can ripen. In my own experience, the self-fertile varieties have a smaller fruit, whereas the main female varieties have bigger fruit. In fact, only this week walking around Lostwithiel I saw a Kiwi from which they obviously hadn’t bothered to harvest all the fruit and they were every bit as big as the fruit you see in the in the shops – just hanging there. They have big, handsome leaves as well, which grow glossy-yellow in the autumn. The flowers are very pretty, about the size of one of those lovely single Primrose flowers, creamy-primrose in colour and with a lovely sweet scent as well. So they’re a climber that’s well-worth growing in its own right, even if you don’t like Kiwi fruit. They’re perfectly hardy, and you don’t have to grow them indoors, unless you don't want to be able to get back into your greenhouse again!
Lavender, how to keep tidy
Q. How long do Lavender plants live? They always seem to look tatty very quickly.
Lavender does have an unfortunate ability to go very tatty very quickly, particularly in this country, basically because it’s too bloody wet! If you think about where Lavender grow naturally – we’re talking about Provence – and all of those lovely hot countries where we’d like to be at the moment (late February), instead of this nice freezing cold wet one! Of course, we’re giving them precisely the conditions that they don’t want, over here, in that we’re giving them wet and generally very cold conditions in the UK, even though the south-west is milder. In fact, the main thing that kills Lavenders or stops them from looking good, is that they’re too wet at the root: it’s not really what happens on top that affects them, it’s what happens underneath that is the real problem. That’s what will make your Lavender look so scruffy, and/or set your Lavender back very dramatically. If you want to get good-looking Lavenders, you need to try and replicate the soil conditions as far as possible. So this means that you need to incorporate plenty of good drainage; you need to plant them on a south-facing situation so that they’ve got maximum sunshine on them; and you also need to try and put them where they don’t catch the worst of the northerly winds: whilst the plants themselves are hardy, the combination of cold, wet, northerly winds and wet at the root is really bad news for a Lavender – they really don’t like it.
The other fatal mistake that people make with Lavender is, because in the autumn it starts to look untidy, they think ‘Oh! We must prune it now, and make it look better.’ This is not a good move, because they’re pruning it at a time of year when it’s desperately trying to go to sleep. Really, all you’re going to do is, you’re going to prune it when it can’t grow out of the damage you’ve done to it with your pruning – you’ve done it with the best of intentions but needless to say, you have created damage. So, if you can bear to leave it alone in the autumn and not fuss about tidying it up too much, it’s far better to give it a good haircut March time, when it’s just starting to come into young growth. It can then grow out of it, put on plenty of young growth for that season and should make a much happier plant, a much better Lavender.
As for varieties, Lavenders are pretty tough as a whole, but if I had to choose a traditional Lavender to recommend, then I would probably go for ‘Munstead’,which has been around for a long, long time, that’s a dwarf. ‘Hidcote’ is good, but there are newer varieties which I think have probably superceded it, like ‘Seal’. But there are quite a few new varieties, particularly some good ones coming out of France, which are well worth having a look-out for. Of course, don’t mistake the ‘French Lavenders’ for traditional Lavenders that have come from France. There’s ‘French Lavender’, which is Lavender stoechys, some people think it has a more attractive little flower with – almost like – butterfly wings coming out of it, but it doesn’t have anything like the same perfume department.
Lawns, alternatives to
Q. Have you any suggestions for alternatives to lawns? I'd like to try something different instead of just grass.
A. This will depend on how much you're likely to use the area. If it's purely decorative, consider lawn Chamomile, but it does need good drainage. You could always be ultra-modern and look at Astroturf. Or, if you want a hardwearing surface but not all concrete, think about slabs or paving, slightly spaced to allow you to plant things like Thymes, Campanulas, Alchemillas etc to soften the effect. One thing is for certain, grass lawns are not a low maintenance option!
Lawns, mowing in January
Q. If the lawn gets too long in January, is it OK for me to mow it?
A. Lawn maintenance in the winter can be very difficult, but so long as it’s not forecast to be very frosty and you can actually walk on the ground, then there’s no reason why not. If you’re going to cut your lawn in the winter then I would recommend that you pick a period when it’s mild, it’s dry and there’s no frost forecast for – ideally – the next few days. But have your lawnmower set on the highest possible setting before you even think about going to get it cut. If you walk on the lawn and your footprints sink, don’t bother, because your lawnmower is going to sink into the lawn as well and the chances are it’s just going to rut your lawn and make quite a mess.
Lettuces in pots
Q. Is it possible to grow lettuces in pots?
A. Oh yes! Eminently possible! You can grow anything in a pot. The pot is only a containerised bit of garden, if you look at it from one point of view. So if you’re wanting to grow lettuce and you haven’t got a vegetable garden, or if you’re want to keep them out of the way of the slugs, then yes they do very well. In fact, you can have this happy little row of lettuces, each one in a pot all sitting there, and they’ll make much fatter, rounder plants very often because of course you can space them out if you want to, so you haven’t got to worry about pinching them out. I can’t remember the variety names, but basically the ones which you just go and pull leaves off rather than pick the whole lettuce – those ones do particularly well in pots because they’re easy to get at, you can pick leaves from all round them: they do really nicely. And you can go for the different varieties, ones like the Lollo rosso, the different reds and greens, the frisées. They can make really quite attractive potted subjects: I’m not exactly sure what a ‘Lettuce hanging basket’ would look like, but you know, I’m sure there’s a first time for everything – that would certainly bugger the slugs, wouldn’t it?
I would look for a minimum of a six-inch pot, but you could probably get away with a smaller pot – you just have to do more feeding and watering. They don’t actually make a big root system, it’s the support that the surrounding soil gives to the root system that’s more important and of course pots are more vulnerable to drying out so a reasonable root-run is better. One of the easiest ways you can do it, and you can rig up quite easily, is a grow-bag: if you can make it a bit of ply or anything like that which it can sit on, get it up off the ground. Don’t just cut out the three little squares marked out for three tomatoes, but cut out about ten small squares and plant lettuces into those ones and you’ll get ten lettuces, without a shadow of a doubt, from one grow-bag. That’ll work quite well. It also works for other things like strawberries, spring onions. Have a ‘salad-bag’ – radishes, lettuces and spring onions.
Lemon Grass, problems with seedlings
Q. I have some Lemon Grass seedlings in a greenhouse which are very pale and not growing well. Any sugguestions?
A.Lemongrass is a fickle little soul, which is generally why it’s quite expensive. It’s not the easiest of plants to grow: in fact it’s a tropical plant and not something that’s at all easy to grow in this country. I would normally say, if it’s looking sad and tired in its seedtray it’s probably temperature-related. It’s been a bloody cold spring and even in a greenhouse there’ll have been massive temperature fluctuations. I would suspect that it is temperature and nutrient sensitive. Depending how old the seedlings are, they may perk up a bit when the weather improves and we start to get some better night temperatures as well. But it’s very difficult to quantify that. You might try pricking some out and putting them on a sunny window sill, but they don’t enjoy disturbance. Basically they’re just not an easy plant to do. If you’ve got them up to the seedling stage you’re doing quite well. So perseverance would be my recommendation, but don’t over-feed them and don’t keep them too wet.
Leptospermum, varied colours from seed
Q. Somebody gave us a Leptospermum scoparium. The tree duly died as they don’t like being moved, do they, but it had hundreds of seeds. These we planted and we now have a lot of young trees in flower with a tremendous range of colours. Is this unusual?.
A. If it was a cultivated variety which you originally tried to move and that set seed, it’s inevitable that the seed-raised progeny will be extremely variable. The flower colours will vary from white to deep pink, almost red; and the habit of the plants will range from dwarf through to full-grown trees. So don’t think you’re going to get all dwarf forms either. They will be hugely variable and this stems back to anything that’s seed-raised that comes from a hybridised variety – they will revert to type. This of course is how you get new varieties coming, from when things are cross-pollinated: the seeds are raised and then they’re assessed on their own merit to see whether any of those ones are worth propagating clonally in their own right. So I wouldn’t be at all surprised to find a mass of variation: probably the best thing to do would be to select (unless you happen to want a Leptospermum forest) 10 or a dozen of the healthiest-looking seedlings – look for a variety of foliage, colour, flower colour, habit variation. Grow those on in containers for a couple of years and see how they’re performing, before selecting those ones which you want to have in the garden. Then maybe donate the rest to friends or local good causes. These seedlings would be the result of cross-pollination within the flowers themselves or from other Leptospermums in the area, just cross-pollinating within the same plant will produce variation. Seed from the plant will not ‘come true’. It’s the same as when you buy a Bramley apple and sow the pips – you won’t get a Bramley apple! Very frustrating!
Q.I have a Leylandii hedge which is 12ft high. What can I do about it?
A. Depending on the age of the hedge, if it is still fairly young you can now reduce it in height to your required preference ( I would recommend between six and eight feet). Similarly the sides need to be trimmed but don't go back into old wood where there is no green foliage. If it's an older hedge, then you can also reduce the height but you may find it more of a problem reducing the width, as once more you shouldn't prune back into old wood. Bear in mind the new regulations regarding evergreen hedges. Six to eight feet is generally acceptable to most people and of course is easier to maintain.
Lychnis, problems with
Q. I was given some Lychnis haagiana seeds, but although the plants flowered, they have all subsequently died.
A. There can be problems growing Lychnis from seed, as it normally grows in very dry sunny positions in hedgerows. Seedlings can damp off very easily so the most important thing is not to overwater. So persevere, as it's worth the effort.
Maize, how to grow
Q. How do you grow Maize?
Maize is best grown from seed and you can buy it quite easily from good seed companies, either mail order, or some of the bigger centres, will have Maize on their seed rack although, admittedly, not many do. You can get ordinary, common golden Maize, or lovely bi-coloured maize which looks absolutely fantastic when you try to cut it. Sow two to three inches deep in the soil, or pre-germinate them in a greenhouse in little cells or toilet roll tubes or whatever takes your fancy. Then plant them out into your vegetable plot, probably 9 to 12 inch spacing if you want to get good, chunky plants, or you can go as close as six inches. The more room you give them, the better, in all honesty, and off they go on their merry little way. I wouldn’t normally recommend that you grow them in a single row – it’s better to grow two or three short rows in a block, because they’re self-supporting in that respect: they do make very tall plants and can be prone to wind-damage. Make sure you’ve got good soil preparation to start with; they need an open, sunny position. They prefer a neutral soil, they don’t like it to be excessively acid. Then, basically, leave them to get on with it. Hopefully, in the second half of the summer, you’ll start to see the flowers – lovely long tassles from what appear to be great fat seed pods forming. Leave them until the flower will pull away, and then you can crop them.
Maples, salt tolerant
Q. I love maples, but our garden is on a west-facing slope about half a mile from the sea, and gets regularly battered by salt-laden winds. Could you suggest a variety of maple which would tolerate these conditions?
A. Japanese Maples won't tolerate salty wind. The only Acers which will grow in these conditions are the Sycamore group which will make bigger trees and may not suit your preferences.
Marram Grass, how to control
Q. I have been searching the internet desperate to find some information on Marram Grass, which is growing like crazy on our local golden sandy beach, that up to now is a Blue Flag area. the questions I want answering are:
Does it grow faster at certain times of the year? How can it be controlled? How can it be destroyed? Are the roots longer than the growth above ground?
A. Ammophila arenaria or Marram grass is a particularly useful native of sand dunes where it helps to bind the sand together. Unfortunately, it doesn't know its boundaries very well and can become quite invasive. It is also rather sharp to walk on in the sand. Like all grasses, they have times of year when they will grow most strongly, and with Marram it is normally from May-July that it is most actively growing. To control it you will need to spray with a glyphosate based systemic weedkiller, such as Roundup. It may need more than one application but it will eventally work.
Q. Are the roots longer than the growth above ground?
A. Yes, they have a questing root and suckering system, so there’s a lot of it underground – there has to be, to anchor it.
Q. Is the Roundup weedkiller dangerous to any human or pet?
A. Yes, it is, but it deactivates on contact with the soil. As long as you keep pets out of the area until it’s dried on the foliage, then it’s fine to let them back in.
Q. Is Marram Grass renowned for attracting any form of wildlife?
A.When it flowers, I have a feeling that butterflies will use it, but I can’t swear to that. Just as part of an eco-system it’s a valuable resource on the dunes.
Maze, how to plan and build
Q. I'd like to create a maze in my garden. Could you give me some advice about how to design and grow it?
A. In general terms, simplicity is probably the key. Obviously, scale will have some effect on the layout, and if you're aiming for a maze which cannot be overlooked or where the walls are above 6ft then the simpler the better. Before you even start planting your main tools are a piece of paper and a pencil. You can - and I would probably recommend this - 'borrow' a maze pattern and if you don't know where to look for one, most children's activity books will provide a good source. There are two main styles of maze. One involves a lot of dead ends, and the principle is that you have to find your way through by trial and error. The second involves taking a very long time to cross a short distance, in other words, there is only one route to follow. The choice of plants however is many and various, from annuals such as the increasingly popular maize to the more ambitious long-term maze which can be made with any hedging plant of your choice, but bear in mind that you're going to have an awful lot of hedges to cut!
Miniature garden, how to start one
Q. I would like to make a miniature garden for my grandchildren. Please can you suggest some suitable plants. It will be in a large, old kitchen sink.
A. You need to avoid the temptation to have all 'teeny-weeny' plants unless you do really want to create an Alice in Wonderland effect. Depending on whether you want to have all groundcover or whether you'd rather have a bit more interest will dictate your choice. For the flatter version, your best bet is to have a look in the Alpine section at your local garden centre. However, beware of the very popular plants like Aubretia and Alyssum unless you want to have one plant only in your sink! Go for the more unusual and the clump-forming species. A few examples include Aquelegia, Armeria, Dianthus and Cotula. Remember to aim for a good mix of foliage colours as well as flowers. For a more textured look I would strongly recommend one of the true dwarf conifers: I stress the word 'true' because sometimes conifers that are offered as 'dwarf' must derive from a different interpretation to mine. Do check with your local centre or ideally go to a specialist. These can then be planted with one or two lower groundcover plants, such as thyme.
Moles, how to get rid of them
Q. How can I get rid of moles in a lawn?
A.Moles are a tricky topic. There are a lot of myths (and flack) attached to the removal of said creatures. I personally am not a great advocate of mole traps – I think they’re nasty contraptions, unless you can get hold of humane mole traps. You can call in pest control people and they will get rid of your moles for you. But if it’s a problem you want to deal with yourself at home, then a variety of methods can be applied. One that I’ve had success with has involved gorse: if you dig down from the hole and find the run, put trimmings of gorse in the run so that they prick their little noses on it and don’t like it. Also, if you can get hold of either badger or ferret droppings (I know it sounds weird!), if you can put that down the run, they don’t like it, because either is more vicious than the moles, which will tend to turn tail and go elsewhere. So anything like that which seems aggressive towards the mole will help.
Monterey Pines, shading a vegetable patch
Q. We have grown Monterey Pines around our vegetable plot in order to shelter it from the wind. These are now about 12 ft high and they’re beginning to shade the plot. Is there anything we can do, apart from cutting them down?
Obviously, these aren’t going to get any smaller, so you’re going to have to make a tough decision at this point. It’s going to be a case of ‘Do I chop it off at the top?’ or ‘Do I start to lift them up from the bottom?’ Now, depending which way they’re sheltering the vegetable patch – which way the sun’s coming in – and you still want the trees to grow up to their eventual height, then the best bet would be to gently start ‘crowning’ them up: this means taking off the bottom rings of branches, a couple of rings at a time every year. But you then have to take a decision whether the eventual height of the tree is going to cast too much shade over the vegetable patch, in which case you’re going to have to consider taking out the tops out instead, maybe even try to clip them as a hedge – but I wouldn’t say they’re the most successful hedging species I’ve ever thought about! I can’t really think of another alternative… the only other possibility you could have is to take the limbs off on the side of the trees against the vegetable patch to try to maintain as much overhead light as possible and maybe this will restrict the amount of shading you have on there.
Moss on lawn
Q. How can I remove moss from a lawn?
Moss on the lawn is inevitably caused by poor drainage. You’ve are two courses of action that you’ve got to take. One, you have to remove the cause of the moss on the lawn, then – two – you’ve got to remove the moss. First one: as I think I’ve probably advised before, you need to aerate your lawn. Now, you can either go out and buy a posy little aerator machine, or you can get your garden fork out and bounce up and down on it, pretending that it’s a pogo stick, run around the lawn with it. Once you’ve stabbed the lawn with it, then go over the lawn with some lawn sand, working the sand down into the holes, preferably using a besom (broom) ideally, or a lawn rake if you can’t get a besom. The sand will go down into the holes and help to aid the aeration.
Then you need to go over the lawn either with a mechanical scarifier or a good lawn rake. It’s very good exercise for a Sunday afternoon after your roast! It’ll help burn off a few calories and improve your waistline. It’s hard work, scarifying by hand, but infinitely more satisfying: you’ll end up with bloomin’ great piles of moss, you could take two or three goes but eventually you will win. But – you must remove the cause.
Mushroom growing is a bit of a novelty and unless you are going into it commercially, the small mushroom kits that you can buy at many garden centres are as good a way as any. If you fancied the proper Horse Mushrooms so reminiscent of misty autumn mornings, one method that can work – but which is by no means guaranteed – is to leave some mushrooms on the grass you wish to ‘seed’, and hope that the spores will give you a crop the following year. On the whole, mushroom production for the amateur is rather hit-and-miss, and in my opinion best left to the commercial growers.
Neem Tree, as an insecticide
Q. I’ve heard of the Neem Tree, which apparently has insecticidal properties. Is it really true that you can fend off insects with it?
Yes, indeed, that is what is used in Africa: the indigenous population will use Neem as a distillation – I think it’s from the bark but don’t hold me to that – which they will use as an insecticide, either to spray on crops or indeed to use as an insect repellent on themselves. I’m not sure that, without further investigation into pharmacology, that I’d want to immediately apply it to myself, but you can use a distillation of it, certainly, as an environmentally friendly insecticide on your crops. I think before you went down that route I would want just to check which bits of the plant it is and how this should be distilled, which proportions you should use, because you could end up causing some problems if you didn’t actually do it properly. But yes, there are several plants that do have insecticidal properties and they’re were used before chemicals became more widely available. We relied on plants to give us the natural protection: it’s only because we’ve become very lazy in the last 150 years that it’s become a lot easier for us to rely on chemicals, unfortunately – we can just go and buy a bottle, it’s a damn sight easier! The Neem is a tropical plant and it’s not the easiest of things to grow in this country, coastal gardens are obviously going to have more success than gardens further inland that are colder, but it’s not something that I would plan setting up an orchard of!
Q. Can you tell me a bit about ‘no-dig’ gardening? It sounds very appealing!
Yes, no-dig gardening is my idea of heaven really. I can always remember my first introduction to no-dig gardening which was a television programme many, many years ago now. It showed somebody who’d bought an old chapel and attached to the chapel wall was, needless to say, a decommissioned graveyard. They had decided that they were going to adopt a no-dig policy, which personally I thought was eminently sensible in a graveyard! And also, if you think about it from a more positive point of view, there must have been plenty of bonemeal in there, quite rich ground really!
The object of a no-dig policy is that you don’t do as most conventional gardeners do. If you've got a vegetable plot you turn the whole plot over , double dig it or rotovate it or whatever the case may be. With no-dig policies, basically you’re looking at minimal soil disturbance. Obviously you need to break soil up to sow seed in it, but what you’re not going to do is this business of double-digging and getting muck working right down. The theory is that you spread your fertiliser and your mulch and your manures on top and you will encourage the worms to take it down through for you and they will then also aerate the soil. So what you must be very careful of with no-dig gardens is that you don’t cause compaction: you need to make sure that you’ve got frequent walking areas so that you’re not walking across the soil, and you avoid any risk of compaction of the soil.
As a system it works extremely well, particularly if you’re lazy like me and don’t really like going around doing double-digging. Weeds are not a problem: if anything there are less weed problems because you’re not disturbing the soil further down and letting other weed seeds come up through to the surface. The old adage of ‘one year’s seed is seven years’ weeds’ is very appropriate, because – sure as your life – you can guarantee that every time you dig up fresh soil, you get more weed seeds come up. No-dig policies tend to avoid that, so they’re quite useful. Again, they’re very useful in stoney gardens or somewhere where digging is a problem, or when it becomes a problem for you physically and then you can change your approach.
Novel or unusual plants
Q. Can you suggest some novel or unusual plants?
Novelty plants indoors are a little bit restricted, but when you consider that you can use most of the plants that you can only find in sub-tropical countries as houseplants in this country, there is actually quite a broad spectrum open to you, although they don’t always enjoy our centrally-heated conditions I suppose. But carnivorous plants in all shapes and sizes do offer fairly dramatic plant material, whether they’re the beautiful hanging slipper-type carnivorous ones with those lovely, bulbous, glistening red cups which attract the insects in, or whether they’re the lovely Venus Fly Traps, which I love and which always attracted me as a child, but unfortunately you have to remember you can exhaust one – if you keep touching its little hairs too often its hinges will fall apart! – so you do need to be careful with those. The nice thing about them is that they live on what you give them in terms of flies, although they do need a certain amount of feeding as well. And for moisture, all you have to do is to stand them in water so that they’re continually moist and then generally they’re very happy. So they work well.
Plants with an unusual smell are quite popular; and although it’s not strictly a houseplant at all, the Chocolate Cosmos is one I’m very fond of – in fact, anything that smells of chocolate, I’m rather fond of! – so the Cosmos is very good. It’s one that doesn’t do outdoors all the year round very well here in Cornwall because of the high rainfall, but I would normally treat it as a tender perennial I suppose, and I’d prefer to overwinter it in a greenhouse or grow it in a tub, enjoy it outdoors on a patio in the summer, then overwinter it in a cold greenhouse just to keep it on the dry side, and then it should come through again fine during the following year. There are one or two others that I quite like growing from a novelty point of view, indoors: one is the Coffee Tree – now don’t ever expect to be picking your own beans, not unless you happen to have your own version of the Eden Project – but it’s a handsome foliage plant and really works quite nicely. Growing avocados from the stones: if you happen to be someone who enjoys Avocados (and personally I think they taste like soap) at least the stone is useful. What we used to do years ago was to push cocktail sticks into it and stand it over a cup of water so that the base was just touching the water; it would start to grow, the fruit would split and then you could pot it up. An Avocado makes another handsome foliage plant for the house: they can get a bit enthusiastic though, so you need to either keep it pruned or give it away to the Eden Project eventually, I suppose! Anything that you can grow from a fruit of something that you’ve eaten, like a date – you can grow your own date palms if you want to – anything like that which you’ve eaten or used has a certain value to it – maybe something you’ve had on holiday which has a certain novelty to it as well. Be careful of some tropical plants, though, they can be very vigorous growers and will very quickly outgrow the space you’ve got available.
As for the Sensitive Plant, it’s a form of Acacia, and again if you stroke your hand along the leaves, the leaflet will close up. Anything that has some sort of reaction like that, I find quite fascinating. But other things react to sunlight: like Lampranthus ( which is the perennial Mesembryanthemum) has flowers that open out in sunshine and close up again. The ordinary, common Celandine does the same, but there is a lovely Celandine which is called Ranunculus ficaria ‘Brazen Hussy’: this is beautiful, it’s got purple leaves like an ordinary Celandine and the flowers are bright yellow when they first open, but as soon as the sun hits them when they open, half of the petal goes white and they look like miniature fried eggs, sitting on a very neat carpet of dark foliage. And it’s totally non-invasive, not like a Buttercup or the wild Celandine – a neat little groundcover plant, really charming.
Nuts to grow for fruit
Q. Can you suggest some nut trees or bushes to grow for their fruit?
A. Nut trees have been grown productively in this country certainly since medieval times. Walnuts are one of the biggest trees: varieties "Broadview" and "Franquette" are mostly self-fertile and highly productive from an early age - you could normally expect fruit from five years after planting. Sweet or Spanish Chestnuts are doing well in this country, enjoying as they do the increasingly hot summers. Again, make sure you choose a named variety if you wish to grow them for fruit. "Maravel" and "Marron de Lyon" are good varieties. Cob nuts and Hazelnuts are very easy to grow, widely grown traditionally in the south-east of the country, but they do well in most areas. With all of these trees the biggest problem you're going to have is small, grey and furry and you will need to beat them to it, especially with the Hazels and Cobs.
Oaks, choice in exposed situations
Q.Please can you suggest types of oak tree for exposed situations?
A. Only certain varieties of Oak will do well in a coastal environment. The best oak for an exposed site is probably Quercus cerris, the Turkey Oak. This is a deciduous oak resistant to most conditions: it makes a tree very similar to an English Oak but it’s quicker growing. If you're in a coastal area you could also consider Quercus ilex (Holm Oak), which is evergreen and makes a broad, dense canopy. Both of them are big trees (50-100ft), so not for your average semi-detached. Another variety to choose is Quercus x lucombeana. Quercus ilex and Quercus x lucombeana are both evergreens and make broad, chunky trees. All these ones will take just about all the salt that’s thrown at them, whether they’re free-standing or part of a copse or a hedge – they will all do well. By the way, oak "apples" are caused by little insects: they are disfiguring but not damaging.
Ophiopogon, poor leaf colour
Q. I have an Ophiopogon in a polytunnel. Its leaves are a bit dull and slightly brown – it’s not really a very good colour.
A. It wants an outdoor holiday! It needs to get out! It won’t enjoy it in there in a tunnel: there’s a certain amount of uV filtered out, it doesn’t get rain to wash it off – even though no doubt you are watering it, it’s not the same sort of lifestyle. Also, Ophiopogon really do respond well to feeding, and if the foliage is starting to go a bit dull, purpley-brown rather than black, that can be a fairly sure sign that it needs feeding. You’ve got two courses of action. One, you can plant it out into some well-prepared soil and it’ll take a while to recover because it’s such a slow-growing plant. Two, if it’s in a reasonably sized pot and you’ve got it in a tunnel, then start liquid-feeding it: general purpose liquid feed will be fine, start pouring it in – it will take a while to respond but it will perk up. But they do respond well to feeding. Personally, I think they’re far better outdoors.
Q. I was sent some seeds from Canada from what is commonly known as the 'Windmill Palm'. Do you happen to know what the true name is and whether it would tolerate salt winds?
A. It is probably Trachycarpus fortunei, and yes, it will grow in a coastal situation. The good news is that seeds germinate readily.
Panax, genus of
Q.When I was in Trengwainton Garden yesterday (near Penzance), I saw two very different trees. One was a Pseudopanax, and the other was a Tetrapanax. Now the Pseudopanax had long thin leaves, hard and glossy, while the Tetrapanax had large papery leaves and was about 15ft high. In view of the difference, what is a 'Panax' tree? These had no similarities at all, so why are both called 'Panax'?
A. The Panax looks very similar to Horse Chestnut, with divided leaves.It has tuberous roots from which Ginseng as we know it is extracted. Tetrapanax has big, five-pointed leaves; Pseudopanax also has leaves divided into five leaflets, so both resemble the Panax.
Patio, choosing plants
Q. We are moving into a new house which has a patio. We can afford to spend about a hundred pounds on plants. Suggestions, please!
A. A hundred pounds could be a fortune if you have a little patience to add, and much will depend upon the effect you wish to achieve. An exotic and lush-looking patio can be achieved quite quickly with one or two carefully chosn evergreens such as Fatsia japonica, various bamboos, e.g. Pseudopanax (depending on where you are in this world as they're not the hardiest of plants) and perennial grasses. Containers can make a big hole in your budget but if you want to spend more on your plants than on your containers, ordinary black plastic pots can be transformed with a couple of cans of car spray paint, so you can be as contemporary as you wish (grey is today's black).
If you want to go for a more traditional look with plenty of flowers then have a look around for some bargains in bedding plants, Fuchsias and Geraniums (Pelargoniums) which can still be planted up to give a nice display now. Finally, it is worth bearing in mind that you can grow anything in a pot for a limited period of time, so let your imagination run riot!
Peach tree not fruiting
Q.I have a peach growing in a polytunnel. It is in its second year. Last year it produced 14 fruit, but this year it has no fruit at all. Suggestions, please!
A. It will depend how vigorously it grew in the first year. But often in a tunnel in its first year it will put on fruit rather than growth, so the fact that it is taking a rest comes as no surprise. It's more important at this stage that it does concentrate on growing rather than fruiting, as this is after all its life-blood.
Phormium, how to move
Q. I have a four-year-old Phormium, about four feet high. I would like to know if I could move it to another position successfully or if there would be problems.
A. It really depends on how long the Phormium has been where it is. If it’s been there for more than four years, then just lifting it wholesale might cause problems, but it really depends on the condition of the Phormium. Usually, they lift and transplant quite well: they’re very often lifted as big plants and divided down for propagation purposes, so there’s absolutely no reason why that couldn’t happen. You could have at least two for the price of one! So, yes, it would be well worth trying, I would say. Doing it now (early February) would be fine: if you’ve got good soil conditions then you could probably do it through to the end of March without too much problem.
Phormium wilting in cold weather
Q. I have a large bronze Phormium that went completely flat in the recent spell of icy weather. What are the chances of its reviving?
A. It should revive well. You may find that some of the outer leaves could be damaged because the ribs would have broken with the weight of snow on them. But as long as the central section of the fan, I suppose, is intact, there is no reason why it shouldn’t shoot up again. Phormiums are, strictly speaking, perennials; and even if you lose the top growth they will usually shoot again from below ground, and an established plant is in fact quite hard to kill, so I don’t see any reason why your plant shouldn’t recover but it may look a bit sorry for itself for the first couple of months. There is a risk of rotting, and you need just to keep an eye on the plant and if you see leaves starting to die back, then cut them off to reduce the amount of dead material around the plant. But otherwise it’s just going to be a case of sit back and wait and see; and hope you get the new growth coming through in the spring. Once you get the new growth, then you can go round and cut the old, tired, tatty foliage away and let the young growth come through and do its stuff. There isn’t any way of preventing this sort of thing happening, unfortunately – I mean you can dash out and tie up all the Phormiums and that sort of thing if you get snow predicted or we get a heavy snowfall, but unfortunately the chances are you’re generally not there when it happens, and by the time you get home it’s almost always too late – the damage is done. I’m not a great advocate of wrapping everything up. Generally things will shrug off the snow and will bounce back.
Pineapples, how to grow
Q. How do you grow Pineapples?
A. Pineapples became popular in Victorian times and really were the preserve of the rich. To successfully fruit in this country they need to be grown in a heated greenhouse and much ingenuity was used by early growers to provide underground heating. To make a hotbed in effect you are creating a raised bed with some sort of heating at the bottom - this can be electric cable, hot air or hot water, but either method allows heat to rise up through the soil and provides both insulation and protection against the cold whilst also encouraging steady growth. They're a fun plant to grow but unless you have a greenhouse dedicated to these crops you may find it too much of a challenge, but - hey - that's what gardening's all about!
Pine seeds, how to pot up
Q. I am trying to grow Monterey Pines from seed, but when I pot them on from the seedtray, they invariably die. Suggestions, please.
With most pines, if they’re grown from seed, they’re best sown into individual pots so that when they’re transferred on they don’t suffer a check at the root. If they’re sown in a seedtray, unless they’re pricked out when they’re very young, the tap root gets broken very quickly and this can cause a terminal check to the plant. So my general advice would be: sow them in individual pots or ideally if you could get little root trainers or trays of plugs, sow the seeds individually in there,. Then when you then pot them on there’s absolutely no check to them. Also, when you pot them on, don’t use too strong a compost. You can use coir pots or make pots from paper, you can even use toilet roll innards – anything like that, really.
Pioneer plants, for growing next to the sea
Q.can you suggest some pioneering plants for gardens on the shoreline?
A. 'Pioneer' plants are those that first move into any area. In a coastal situation they have an especially hostile climate to cope with. What you wish to do in any given area - create shelter or cover the ground - will dictate your selection of plants. For shelter, a mixture of evergreen shrubs and conifers usually offers the best chance. Some of the toughest plants include Olearia, Grisellina, Escallonia, Laurel, Cupressus and Tinus. Again, your selection will be governed by height requirements. For ground cover, take a walk along any coastline and you'll see nature provides a fair selection without any help from us, so it pays to mimic whenever possible. Lampranthus, Erigeron, Armeria (Thrift), Thyme, Rosemary and the fine-needled grasses will all take extremely exposed conditions. But in all honesty, you have to remember that few plants would choose a coastal situation for growing in. At best they will tolerate it. To see one of the best coastal gardens for an extreme situation, visit Headland at Polruan.
Pittosporum, fungus on
Q. What causes a black smuttiness on Pittosporum leaves and what can I do about it?
A. This is probably the same as Black Soot on Camellias, which is caused by honeydew from aphid infestations. Check for greenfly and treat accordingly.
Plum trees, growing in coastal areas
Q. Is it possible to grow plum trees and other fruit trees in coastal areas?
A. Plums and indeed most common fruit trees such as apples and cherries will grow in a coastal situation. I'm not going to say they will thrive, but they will certainly grow well enough to produce good crops. As far as varieties are concerned, beware of the more vigorous varieties which may be more susceptible to physical damage from the wind. Good varieties of plum to look for include 'Czar', Marjorie's Seedling and the damsons (unbeatable for gin and jam!).
Polytunnel, choosing vegetables & fruit for
Q. Please can you give me some suggestions for vegetables or fruit we can grow in a polytunnel.
A. A huge range is available, depending on how exotic your tastes are. You can use a tunnel to extend the season of various crops such as early potatoes, strawberries, runner beans etc. - there's nothing like eating your first new potatoes when the ones in the shop are like gold-dust. But if you feel a little more ambitious you can try growing crops that demand higher temperatures and warmer climes. So, try chilli peppers, which can be dried for winter use, delicious plum tomatoes and okra (also known as Lady's Fingers), possibly an acquired taste but fun to grow. Look out for seeds from Franchi, an Italian company which offers a range of vegetable seeds with real flavour. Indeed, pop an olive in there and you could pretend you were in Italy! - not necessarily a cultivar, Oleo Europeus will do.
Pots with creepy-crawlies
Q. I keep finding various forms of wildlife in my plant pots, e.g. worms, centipedes, woodlice and earwigs to name but a few. Do they do any harm?
Q. Every year the foliage on my potatoes suddenly wilts and shrivels. Is this Potato Blight? What causes it and what can I do to prevent it?
A. Potato Blight is the bane of gardeners' lives and it's worth remembering that it can spread to your tomatoes as well. Potato Blight is like the flu, you can prevent it but you can't cure it. If you know your garden is prone to Potato Blight, or if you have had Potato Blight before, I would recommend spraying Diathane 945 from early in the season as soon as foliage emerges, at the recommended intervals, for protection. However, if it's too late for that, then as soon as you see evidence of Blight on your patch, cut all the affected foliage away as this may slow down the spread. But if you get it late enough in the season, your potatoes should have formed and can be lifted and used safely.
Potatoes, growing new potatoes for Christmas
Q. How do I grow some new potatoes in time for Christmas?
A. Potatoes for Christmas are a lovely idea and even if you haven't got a vegetable patch you can still indulge yourself. They need to be planted indoors in a greenhouse or conservatory, and the easiest way to do it is to get a large empty compost bag, i.e. 75 litre, and roll it down until you've made an irregular pot 18" deep. Fill this with 12" of good compost (or compost and soil mixed) and get your chitted potatoes in before the end of September. Then all you need to do as the shoots grow is to top the bag up with more compost, unrolling the sides as you go. Come Christmas, you can then cut into the bottom of the bag and start harvesting. Seed potatoes won't be widely available at this time of year, but you could use your own potatoes from your maincrop, or even use some old, smallish potatoes bought from the shop.
Potentillas for exposed gardens
Q. Please can you suggest varieties of Potentilla to grow from seed in exposed positions?
A. Potentillas, either shrubby or herbaceous varieties, are good for exposed sites but the shrubby ones are propagated by cuttings not by seed. I suggest you try Chiltern Seeds for herbaceous varieties, at www.chilternseeds.co.uk.
Proteas, not flowering
Q. Why isn't my Protea flowering? It's outside in a sunny situation.
Proteas are South African natives and as such they enjoy much sunnier weather than we do. They require hot, dry conditions for longer than your average English summer of three days!
Pumpkins, how to grow enormous ones
Q. How do you grow really enormous pumpkins?
Pumpkins are gross feeders and, like all cucurbits, they will benefit from good soil preparation before you even start to think about where to plant them. The seeds are best sown in pots so that they get off to a good start before the slugs get at them. Once they up probably to about 6 to 9 inches tall and growing strongly, they can be planted out, but they should be planted out to a patch of ground that has been well manured. Ideally this should be done in the autumn, but the well-laid plans of mice and men are such that, with the best will in the world, we don’t all get round to manuring the ground in the autumn when we should! – it can be done in the spring, but with well-rotted manure – farmyard manure or your own garden compost – and that should be dug in and mixed in well with the existing soil. The pumpkins can then be planted out. Basically, don’t be afraid to throw food at them every two minutes! You can throw as much food at them as they want and they will eat everything you give ‘em! But the key to getting a good pumpkin is starting off with the right seed: it’s no good going for the smaller, ornamental varieties which are designed for food – the smaller pumpkins are the ones that give the better flavoured flesh (as far as you ever get flavour from a pumpkin) but if you want to go for ‘gi-normous’ in the pumpkin department, then go for selected seed which you can either collect from someone who grew enormous pumpkins the year before, or you can get specially selected seed that’s intended for exhibition varieties. Robinsons Seeds, particularly, do a very good range of large specimen varieties. Once they’re growing and the fruit’s forming, continue to throw the food at them: basically, it’s feed-feed-feed. Pretend it’s a small child – keep throwing the food at it and bear in mind that it’s got the advantage you don’t have to change its nappies!
Rabbits, how to deal with them
Q. How can I keep rabbits out of my garden?
A. Rabbits are probably one of the worst pests in some gardens, particularly in rural areas. Keeping them out of the garden can be tricky and expensive. The obvious solution is rabbit-proof fencing, though if you have a large garden this can cost a lot of money because the fence needs to be three foot high above the ground and there also needs to be a minimum of 12 inches below the ground because the little darlings do have a habit of digging under it and that’s the only way in fencing terms that you can keep them out. Now if that’s not a possibility for you, then you need to look at planting things that don’t attract rabbits. There’s a very useful little book called ‘Gardening with the Enemy’, it’s a fairly small book written by a lady who gardened on the chalk bank where rabbits were a serious problem. By trial and error she learned which plants would tolerate living with rabbits – the ones that the rabbits would leave alone – and also a few other tricks of the trade which she’d learned along the way about how to cope with them.
But if you get rabbits that are using the garden as a route, you can sometimes deter them by using a product called Renardine which smells disgusting: you soak kindling sticks in the Renardine and put them in the path of the rabbits’ route and the smell will help deter them and hopefully send them on their wibbly way elsewhere. It is also something that is recommended if you’ve got badgers or foxes going through the garden as well. So deterring them helps. Similarly if you’re able to get hold of fox droppings and put them near where the rabbits are coming into the garden, unless it’s a kamakhazi rabbit, that will help to stop it from coming in.
There is, of course, a slightly more final resort, which I’m afraid is shooting them. We have had rabbit problems at the nursery, and I’ve had no compulsion about going up there and getting rid of them with my rifle: it’s a good shot, it’s far better than trapping them or poisoning them – and I have to say rabbit tastes very good afterwards! If you get them out of the garden, sometimes they’ll stay out – but if it’s turning into a persistent problem, I find one quick bang solves it. You have to make a decision, what’s the best way of dealing with it, and from my point of view, they’re not wasted – I like rabbit pie. And they don't suffer, a quick shot is better than being torn to pieces by a fox. I know some people don’t like it – they don’t like seeing anything like that quite so close. If you haven’t got your own rifle, then find a man who can! There are plenty of people out there who will come round and cull your rabbits for you: they’re usually quite happy either to keep them for themselves or to flog them off to the local butcher. So don’t be afraid of asking. If you’re not sure where to go for help, if you have got a severe rabbit problem and you don’t know where to find somebody who can control them – and you’d rather see them shot cleanly than trapped or poisoned or gassed – then get in touch with the local shooting club, you’ll find them listed in your local Yellow Pages, and they’ll usually have neighbours living near you who can come out and deal with the problem for you.
Radishes, different sorts of
Q. Could you tell me a bit about the Radish family – there are all these different sorts –some of them a lot more useful than others, perhaps?
A. I’ll say upfront that I’m not a vegetables expert, but you can nowadays get a huge range of radishes, some of which are really quite pretty, rather ornamental beasties. They are obviously all closely related and they all have varying levels of ‘heat’, for want of a better description, in terms of the pepper-iness of the flavour. But they’re all very similar: I think you’ve got to be a real radish nut to start finding the differences between them. But certainly some of them are very, very colourful and some of them have rings right through them. You can get quite long, cylindrical radishes, very small round radishes, red ones, white ones, pink ones and all variations between. Some of them are more suitable for stoney soil: you can in fact get radishes that are quite pointed like carrots which will do well. So there’s something for every situation. I wouldn’t have said that radishes are like Chilis – they haven’t got that collector-status - people now have Chili Festivals, apparently: I don’t think radishes are ever going to reach that level! I’m not sure that they’re ever really going to become vegetables to set the world afire. But they’re quite fun, they’re easy to grow and they’re a nice crop to get children growing as well, because they’re all very rewarding and they’ll almost always give you a good crop even when you’ve got slugs around in the garden.
Q. When should I re-pot perennials in pots outside?
They can be done any time, but now (mid-March) is a particularly good time. Depending on what your perennial is, you could take advantage of 'now' to divide them, getting two, three, four for the price of one and make lots of little babies out of them. Depending again on the perennial, you could just split some small pieces of the side (leaving the main piece whole) and again, make some young plants for planting out in the garden, giving away or doing whatever you want. But even if you don’t want to do any division, you certainly should be looking at potting them up now. Most perennials prefer to go into a reasonably rich compost, so a John Innes No 3 would be ideal, or a good multi-purpose compost. Break away any old soil that’s easily got rid of, clean off the top of the pot, re-pot them, off they go, should be hunky-dory. Now is a good time to do it.
Rhus (Sumach), how to control suckers
Q. How can I get rid of Rhus (Sumach) suckers? They’re tramping all over the lawn.
Rhus, in the right place, is a lovely plant, but Rhus in the wrong place is a monumental pain-in-the-neck. Unfortunately it is a suckering plant – a suckering, woody, plant – which makes it one stage worse than something like Couch Grass. So the best way to deal with it, if you have an unwanted invasion of Rhus, is to use a product called SBK (‘Special Brushwood Killer’). You’ve got two options, really. You can spray the plant and it will take it back into the stems, get into the root system and kill it; or you can also cut the stems if they’re quite thick and put a product called ‘Root Out’ on to the stems which again is a crystal and you sprinkle it on to the top and put a plastic bag over it to keep the weather off, and that will be taken back into the stem and that will go back in and kill the roots. It may take you two or three goes at it to get rid of it – it is a bit of a pest. Personally, I think they’re lovely when they’re looking good with their autumn colour on, but when they suddenly develop a thicket instead of a single stem, yes, that’s a pain.
Rhododendrons for small gardens
Q. Please can you suggest varieties of Rhododendron or Azalea for a small garden?
A. A. Rhododendrons have a huge range of dwarf- and medium-sized varieties. But without listing hundreds, one of the best groups to look at are the Yakushanium hybrids which flower very freely, usually in May and June. With Azaleas (which are strictly speaking Rhododendrons anyway), all of the japonica varieties are suitable, it's just down to colour choice. The scented Azaleas which are very popular can outgrow a small garden. so unless you've room to spare are probably best avoided.
Rosa rugosa, how to control
Q. How can I control Rosa rugosa – Sweet Briar?
With great difficulty! Rosa rugosa is a gorgeous plant but it does have this nasty habit of suckering, and it’s useful to be aware of that before you actually start planting it, so that you can at least keep it under control. But if you’re inheriting, or you’ve got one and you didn’t realise that it had got out of control, the best thing is to go round the plant with a spade and hack down the suckers that you don’t want, and literally dig ‘em out. You may find that quite a lot of them have got roots and you may be able to use them for hedging elsewhere, giving them away to friends – whatever – although you may have to give them away with a health warning! If you were wanting to get rid of one, then obviously you could spray it with a Glyphosate weedkiller, or a special brushwood killer to actually kill the plant, but that seems a travesty, they are lovely things in their own right. If you’re growing it as a hedge and you don’t mind it getting a bit thick, then allow the suckers to come but every February give it a serious short-back-and-sides – and I mean serious! Take it right back down to four to six inches above the ground; and at that point, if you decide it’s getting too thick, it’s a lot easier for you to get in there, then, and cut any shoots out that are coming out too wide because you can physically wrestle your way into the plant, chop them down and take the additional roots out that you don’t want. So I’d probably go for that approach – chop them back in February and cut out the suckers that you don’t want.
Rosemary plants dying
Q. I have some Rosemary plants - a trailing variety - growing outdoors in pots, but the leaves are going brown and then they die.
Scented garden, choosing plants
Q. Can you suggest some scented plants for a fragrant garden?
Scent in plants is probably the most important criterion for any plant for most gardeners. Add to that, if it's evergreen and low maintenance, you’ve probably got the perfect plant! Obviously there is a huge range of plants that are going to give you perfume. Without filling the entire website with a gargantuan list, what I will do is to home in on some that I think really are worth their space, and are some personal favourites of mine. Daphne odora ‘Marginata’ is probably one of the best winter strongly-scented shrubs that you can find. It’s evergreen, and it likes to grow in a reasonably well-drained soil in a sunny position. The flowers will be starting to come out any time after Christmas. It has small, pink and purple flowers and the perfume is stunning – it’s almost overwhelming if you stick your nose inside a flower; and it will perfume a whole patch of the garden – very well worth its space. Peony ‘Duchesse de Nemours’ is one of my favourite herbaceous Peonies: the flower itself is almost pure white on the outside and very full double, and the central petals are deep butter-yellow. The colours fade from one extreme to the other. I can best describe the perfume as Lux soap, it’s not a flowery scent, it’s very definitely a perfume and it’s a beautiful scent in the garden. Viburnums in all shapes and sizes, most of them have gorgeous perfume, particularly the early spring-flowering ones. If I had to single out a favourite I suppose I’d probably go for Viburnum burkwoodii ‘Park Farm’ hybrid, or ‘Anne Russell’, both of which are pink in bud, opening white, have a divine perfume and are semi-evergreen. They’re reasonably big shrubs, around five to six feet tall and wide, so they need somewhere to give them a fair amount of room. Skimmias are another group of fairly-underrated plants which give very good value – lovely perfume – and on the females (if you’ve got a little ‘boy’ nearby to hold their hand) will of course give you a lovely berry display in the winter and plenty of berries for picking. Interestingly, if you look at most of the plants that are scented, they generally flower in the winter and the spring because the flowers themselves need the perfume to attract insects for pollination, whereas in the summer the flowers can be bold and flamboyant because the weather is better, and they can use colour and a big, big display to attract the insects. In the winter and the spring they have to be more sneaky and they get their friends to come and visit them through slightly more subterfuge. I suppose another plant I would pick for scent, quite different, would be Cercidiphyllum japonicum, which is the Katsura Tree: this one is for the foliage in the autumn when it gets the first frost on it and smells just like candyfloss or burnt sugar. It’s wonderful: all the foliage goes yellow and pink when it gets that frosting on it, and it smells – edible!
Rotation of crops in vegetable patch
Q.Q. Please can you suggest a crop rotation for a small vegetable plot?
A. The key with rotation in a vegetable plot is to group the same sort of vegetables together. So all the Brassicas would class as one group; all the root vegetables are classed as another group and all the Legumiaciae are classed as a third group. If you put them that simply you rotate them – three years is a minimum that you rotate – if you have room to do it for longer, then all well and fine: but if you can do a minimum of three years by alternating those three groups, really you’ve got it sussed. On top of that you also add onions and they would probably make a fourth group of bulbous vegetables. It depends on what your priorities are, but I’ve known people who’ve grown runner beans on the same ground year in, year out and will find eventually that the soil gets exhausted. But anybody would sensibly look at rotating vegetable crops to get the best out of the ground.
So I would look at having potatoes in the ground one year, maybe cabbages or cauliflowers in the following year, possibly onions the third year and runner beans the fourth year, carrots the fifth year and so on; so that when you come back to another group try to choose another member of that group to put in there. Obviously it depends on the room that you have and what your priorities are. The salad-y things are easy, they don’t really have a major problem because they’re not in the ground for long. So long as you can turn the soil over and add plenty of well-rotted farmyard manure or your own garden compost, we haven’t really got an issue with those ones: it’s really the ones that are in the ground for six months or longer that you have a major issue with, you can inter-crop with your salad stuff. But even if it’s a small plot, it needs to have four rotations or three is an absolute minimum.
Tomatoes outdoors in pots
Q. Could you make suggestions for the best-flavoured varieties of tomatoes to grow outdoors in pots?
It depends, really, on whether you like large tomatoes or small ones. I always prefer to go for the small ones: I would go for ‘Gardeners Delight’, and ‘Sungold’ which is a lovely yellow-fruiting variety. ‘Shirley’ is also a good variety. I suggest that if you really want to go for tomatoes with good flavour, get one of the Franchi range of Italian seeds. Most of them are plum tomatoes, which are the ones that everyone grows down there: they do have ones for outdoors and indoors – I’m afraid the flavour knocks spots off the ones which you get in this country, a vastly superior flavour. Plum tomatoes don’t always crop as heavily, but are well worth going for.
Rubber Plants, cutting back
Q.Can Rubber Plants be cut back?
Rubber Plants can be cut back quite happily. The Ficus family are actually very well-behaved and you can prune them very successfully. But if you try to prune a very old, tired plant and expect it to shoot without your doing something else to it, you’re asking a little bit much of it. What you really need to do if you’re pruning your plant is to give it a good feed, making sure that the roots are in a position to actually have a bit of get up and go so that it can regenerate and shoot away quite happily. You can prune Rubber Plants pretty severely, give them a good feed, a good water, put them in a sunny position and hopefully, off-they-jolly-well. Bear in mind that they will weep: the sap will leak out of the cuts initially and it can look a bit messy initially. But don’t worry about it.
Saffron, how to grow for cooking
Q. How do I grow Saffron for culinary use?
Saffron comes from Crocuses and you can buy the proper Saffron Crocus, but don’t ask me the Latin name now, because I can’t remember which one it is. You buy the bulbs in the autumn. You can grow Saffron over here: it’s the actual stamens of the flowers that are picked and dried to make the Saffron strands – not the sort of thing you’re going to be doing by the hundredweight! – which is why Saffron is so expensive, because it is collected by hand mostly in Turkey and Mediterranean countries from the hillsides where the Crocuses flower. And strangely enough, it all comes round the country to Cornwall. I don’t know why, but Cornwall is a country that has a reputation for using Saffron in conjunction with Indian and oriental cooking. Cornwall has this very strange affinity for Saffron. So yes, you can buy the Crocuses, you can grow them, but I wouldn’t guarantee the calibre of Saffron that you will accumulate. Just pick the stamens, put them on paper, put them into a warm, dry area and let them dry.
Scented garden, choosing plants
Q. Can you suggest some scented plants for a fragrant garden?
Scent in plants is probably the most important criterion for any plant for most gardeners. Add to that, if it's evergreen and low maintenance, you’ve probably got the perfect plant! Obviously there is a huge range of plants that are going to give you perfume. Without filling the entire website with a gargantuan list, what I will do is to home in on some that I think really are worth their space, and are some personal favourites of mine. Daphne odora ‘Marginata’ is probably one of the best winter strongly-scented shrubs that you can find. It’s evergreen, and it likes to grow in a reasonably well-drained soil in a sunny position. The flowers will be starting to come out any time after Christmas. It has small, pink and purple flowers and the perfume is stunning – it’s almost overwhelming if you stick your nose inside a flower; and it will perfume a whole patch of the garden – very well worth its space. Peony ‘Duchesse de Nemours’ is one of my favourite herbaceous Peonies: the flower itself is almost pure white on the outside and very full double, and the central petals are deep butter-yellow. The colours fade from one extreme to the other. I can best describe the perfume as Lux soap, it’s not a flowery scent, it’s very definitely a perfume and it’s a beautiful scent in the garden. Viburnums in all shapes and sizes, most of them have gorgeous perfume, particularly the early spring-flowering ones. If I had to single out a favourite I suppose I’d probably go for Viburnum burkwoodii ‘Park Farm’ hybrid, or ‘Anne Russell’, both of which are pink in bud, opening white, have a divine perfume and are semi-evergreen. They’re reasonably big shrubs, around five to six feet tall and wide, so they need somewhere to give them a fair amount of room.
Skimmias are another group of fairly-underrated plants which give very good value – lovely perfume – and on the females (if you’ve got a little ‘boy’ nearby to hold their hand) will of course give you a lovely berry display in the winter and plenty of berries for picking. Interestingly, if you look at most of the plants that are scented, they generally flower in the winter and the spring because the flowers themselves need the perfume to attract insects for pollination, whereas in the summer the flowers can be bold and flamboyant because the weather is better, and they can use colour and a big, big display to attract the insects. In the winter and the spring they have to be more sneaky and they get their friends to come and visit them through slightly more subterfuge. I suppose another plant I would pick for scent, quite different, would be Cercidiphyllum japonicum, which is the Katsura Tree: this one is for the foliage in the autumn when it gets the first frost on it and smells just like candyfloss or burnt sugar. It’s wonderful: all the foliage goes yellow and pink when it gets that frosting on it, and it smells – edible!
Sea Buckthorn, growing from seed
Q. I tried growing Sea Buckthorn from berries, but only one came up. Do they need an alkaline soil?
A. Sea Buckthorn - Hippophae - is a very good coastal plant, with silvery grey foliage and surprisingly showey orange fruit. As you may guess, the fact that it grows well on the coast means that it prefers a well-drained soil and a sunny position. If you're planning it further inland, then make sure it will not get waterlogged. If you do try raising these from seed, you have to bear in mind that nature will have employed a little bird to assist in the germination of the berries. As the seed passes through the bird's gullet it is stripped of all the flesh and the seed itself is slightly abraded. With harder seeds this contributes to the germination. So if you want to try seed-raised ones, put the fruit in a bag with some gravel and give 'em a fairly brutal shaking: then sow the seed. It doesn't enjoy any extremes of soil type: drainage is its main requirement.
Seaweed, using as a fertiliser
Q. Can you tell me about seaweed as a fertiliser?
Seaweed is a very old fertiliser that has been used for literally thousands of years in coastal areas; and indeed it used to be a source of income for people living on the coast who would drag it up and take it inland to farmers and people who wanted to use it. It is a very good, rich sort of fertiliser, but the trouble is – it’s not a case of going off down to the beach and bringing a few bucketloads back and tossing it on to your rhubarb, because as you can imagine the seaweed itself is very heavily contaminated (if you like to use the word) with salt. The way that seaweed should traditionally be used, in a garden situation at least, would be to bring it up – and bear in mind that you’ll need to have a license to take away seaweed. Seaweed is not a freebie and you need to have the shore owner’s permission to take the seaweed away. Then it should be stacked up for twelve months and the rain allowed to do its business, it will degrade it a little and the salt will be filtered out. Then you can put it out on the garden, with the greatest of pleasure – it’s excellent, seaweed, got a very high iron value and it’s generally all-round good stuff. Very good to put in your compost heap, as well, so it works well in both directions.
But, as I say, the main thing to remember is that you need to have a licence for taking away great quantities: if it’s the odd bag here or there, nobody’s going to take a great deal of notice but if you’re going down there with a tractor then it’s a good idea to ask the owner’s permission! I’m not sure whether you have to pay or not, but basically you need to have the permission of the landowner – one comes to an ‘amenable arrangement’.
Seeds to sow in August
Q. What seeds can I sow now (second week of August)?
A. Biennials and perennials can be sown now to produce young plants ready to plant out this autumn or next spring or to make a lovely and unusual (C-word!) present. You could put late crops of salad in now, and you could contemplate sowing seed potatoes now to give you lovely out-of-season new potatoes around (C-word) either indoors or out. You could also consider growing wild flowers on an upturned turf in some rough grass: the soil is impoverished there, so this reduces competition.
Seeds to grow in January
Q. Are there any vegetable seeds that one can sow under cover in January?
A. Oh yes, loads of them! You certainly should’ve been sowing your onions by now, in fact you should have got them in before Christmas, ideally. If you’ve got a heated greenhouse you could look at sowing early tomatoes if you wanted to get them off to a very early start, similarly courgettes if you wanted to. You could sow trays of some of the brassicas to plant out later on, which you could put into a cold frame and get them going, so you could look at your caulis and spring cabbage and that sort of thing if you wanted to sow them into plugs to plant out rather than directly sow out into the garden. If you’ve got a propagator in an unheated greenhouse, that’s fine if you’ve got a frost-free environment for them when they get too big for the propagator – which will happen very quickly with courgettes and tomatoes: so unless you can provide them with a frost-free environment I wouldn’t look at starting those ones off yet unless you live on the coast and frost is not an issue . So there’s quite a wealth of them, and if you trod off to your local centre you’ll find there are a lot of seeds to be had. It’s worth looking out as well for some of the more unusual seeds: particularly, have a look at the Franchi seeds, which are a really good range of Italian ones with a lot of flavour and a lot of good varieties in there and a lot of these are extremely successful. And they do an organic range.
Seed, harvesting and storing
Q.What is the best way to harvest and store seeds?
A.Seeds are best harvested when the first seed pods begin to split naturally. However, this is a gross generalisation as many varieties have quite specific individual requirements - indeed some seed requirements are quite bizarre.
As a rough rule of thumb, imagine what would happen to the seed if the plants were growing in their native country, and this will often give you a clue as to how to harvest and store them. Generally, seeds are best dealt with when fresh. If you need to store seeds before sowing, only keep them in PAPER bags. Plastic causes the seeds to sweat and they will then go off. They should only be harvested in dry weather and once in their paper bags should be stored in a cool, dry place (not a fridge).
Choosing shrubs for shelter hedging
Q.Wonder if you can help? I have friends living 500 metres from the coast in north Kerry, Republic of Ireland. The site is around 50 metres above sea level with open fields and ditches from the house to the sea. They would like a hedge planted along one boundry (aprox 80 metres in length) to act as a wind break. The hedge need not be more tham 1.5 metres high as the view is beautiful. Some shelter is required, however, as the winds and rain in winter can be quite severe They do have young children. Could you suggest any suitable plants? Any help here would be greatly appreciated.
A. One of the nicest hedging plants, which in fact is used very extensively in your part of the world, is Fuchsia riccartonii and it would certainly be the one that I would recommend for your friends to use as a hedging plant in this situation. It will take pretty much most of what the sea can throw at it; it grows rapidly; it will be very prolific in flowering and look extremely pretty. It usually doesn’t grow any taller than about 1.5m – and if it does, it’s very amenable to a brief haircut. So it’s an ideal plant for that situation. For planting as a hedge I would probably put the plants in at about two foot (60cm) apart in a single row, where they’ll be really very happy. If you wanted a fatter hedge you could do a staggered row, but I personally would go for a single row because they’ll thicken out and look extremely well. I think it would be an excellent choice to put in there.
If they didn’t want to go the Fuchsia route, then I suppose I would probably consider Escallonia next, and I would probably go for Escallonia macrantha, which again is a wide one, very free-flowering and better against the salt than E. ‘Crimson Spire’ or E.‘Red Hedger’ which are the ones that are more normally offered. So I think they would be my two favourite options. Other hedging plants which you see offered generally in a coastal situation will do well, but in fact they may in fact do too well and grow too vigorously and become too big, so I don’t think they’re going to fit the bill for your friends.
I think those two are my favourite options for your friends.
Shelter hedging for livestock
Q. Can you recommend shelter hedging for a field with livestock?
A. We’ll look at this from two points of view – evergreen and deciduous. It’s probably easier to look at the things you need to avoid, one of which is Laurel which is a serious no-no for stock. You also obviously need to avoid Yew and I also recommend that you avoid all forms of evergreen Prunus, so that would not just be the ordinary Laurel but also avoid the Portuguese Laurel just to be on the safe side – livestock doesn’t thrive on those particular plants
If I was going to look at an evergreen hedge in a stock area, it needs to be something that will tolerate the odd munchings as they go past. Again, it would depend how tall you want to maintain that hedge, but two of my favourites for an exposed coastal situation would probably be Euonymus japonicus which has got lovely evergreen, glossy foliage but it also has quite fun seed pods on it, but again not toxic so wouldn’t cause a huge problem. The other is Elaeagnus ebingii, which I personally love: the perfume of the flowers is delicious – grossly underrated, it’s such a lovely plant. Another evergreen you might want to consider is Pittosporum. Now if you can get hold of Pittosporum crassifolium – which is the one normally grown on the Isles of Scilly – it’s not that frost hardy so you would only be able to grow it in the very mildest parts where there really is no frost. But of course you could look at Pittosporum tenuifolium as well, which is another very good doer: again, lovely scented flowers, dark purple. Both of those ones make a cracking hedge. But if you want it a bit prickier you could look at some of the variegated forms as well. Griselinia would be a good choice: it’s very vigorous, uprightly so and it will tolerate a certain amount of being munched, it just looks rather disfigured when it has been munched I suppose is the honest way of looking at that. But they would be my choices for the evergreen hedges.
For the deciduous ones, I’m always very tempted by the thorns, the Quickthorn and the Blackthorn mixed together, because they both will give you beautiful blossom but they’ll spread over from the Blackthorn, giving you blossom in March and the Quickthorn giving you blossom in May. Into that you can introduce a few other native species like Hazel, Field Maple, Rowans to make a sort of native style of hedge. If you’re wanting something a little bit more formal, avoid Beech because unfortunately Beech will burn like hell in a coastal wind, so it wouldn’t be my choice as a single species. Hornbeam will do better, but for a deciduous coastal hedge maybe Ramnus frangula and of course Tamarisk is a very flopsy, open, lose thing but it’s a very traditional coastal hedge and it will tolerate just about anything the sea can throw at it, plus of course it’s got beautiful flowers and it’s not toxic. So any of those species would do very nicely. But you’ve really got to think, what style of hedge do you want – do you want it formal? Do you want it informal? Do you want it to look native? Do you want it to look like an obviously cultivated hedge? You need to give it those considerations. Of course you can consider one of the conifer options – Cupressus macrocarpa lutea which is another one that isn’t poisonous, again will take everything the sea can throw at it, nice golden, evergreen foliage, eminently clippable whether by teeth or by hedgetrimmer.
Shredder, how to choose
Q. How would you choose a shredder, and what sort of things would you use to make a mulch?
Firstly, you need to decide what sort of things you’re going to be shredding. Are you talking about greenish material, twigs, wood – what is the sort of material that you want to use? Once you’ve made that decision, have a look at the various shredders that are around: there are some fairly good ones but I would generally say, go for a make that you recognise – a well-known one rather than a cheap special offer from your local DIY, which isn’t always the best value long-term. As far as mulching is concerned, once it’s been shredded you can used it as a mulch immediately, but material very often, as it breaks down, will take nitrogen out of the soil, so you will need to think about putting additional nitrogen-based fertiliser down when you use it, if you’re going to go down that route. Otherwise, you can shred it and put it into a compost heap, which will speed up the composting action and give you some very good compost in a very short time.
You can get petrol-driven shredders, but they are for pretty serious, heavy shredding. Electric ones will do most gardening and domestic uses without too much problem, so you have to decide what sort of use you want out of it. Anything that’s shredding a couple of hundredweight every weekend, then I’d say you’re looking at a more heavy-duty petrol one. As for noise, yes, they are quite noisy and you ought to have ear-protectors if you’re using any shredder, and it’s better to use a little and often rather than long-term use, because you can end up causing yourself some ear damage. Petrol ones are noisier than electric ones. As for neighbours? They don’t shred well…. In Germany, you’re not allowed to mow your lawn, or shred or use any electrical equipment in your garden on a Sunday, but no such law exists in the UK so it’s down to a matter of common sensitivity in all honesty. If someone starts doing that sort of thing at nine o’clock on a Sunday morning, I get a bit miffed, but generally it’s a matter of common sense.
Shrub for small garden
Q.I am looking for a shrub to grow up against a wall. It needs to be no more than five feet high, and to tolerate shade. If it had nice flowers, that would be a bonus!
A. For a semi-shaded position, there is quite a wide selection available. Viburnum tinus (and its cultivars) is a very easy shrub which is amenable to clipping immediately after flowering to keep it within bounds. Skimmias would also suit the situation, but they tend to get wider than they are tall, so that may influence your decision. Hebes - and there are tens of dwarf varieties to choose from - will give you months of colour with flowers and provide neat rounded bushes. Dwarf Rhododendrons, whilst giving their all in the spring, look out for some of the varieties that have beautifully coloured young growth sucha s Rhododendron 'Elizabeth', a red-leaved form.
Slug killer, liquid
Q. Is there a liquid slug killer I could use, instead of using pellets which could poison wildlife?
A. Liquid slug killer is ideal for anybody concerned with birds getting poisoned in the garden. The liquid slug killer is applied to the soil and the slugs are poisoned underground, so there is no risk to other wildlife. The main drawback is that rain will quickly dilute the effect, so re-applications will be necessary.
Soft fruit, growing in tubs
Q. Is it possible to sow currants and gooseberries or other soft fruit, in tubs on a patio?
A. Yes it is, but you have to be very careful about watering. The advantage of growing all these plants in the ground is that they have a relatively constant level of moisture in and around the root system. In a container, the water levels fluctuate madly, from when you water them to just before you water them again; and it can put the plants under tremendous stress. So if you’re going to try to grow fruit in a potted situation, I would either recommend that you look at a trickle irrigation system, or make sure that the tops of the pots are well mulched: you can do that with gravel, with rings of carpet – all sorts of things – anything that helps to retain the moisture in the soil and stops it from transpiring will help to regulate the levels of moisture in the pot. For every plant there is a pot the right size, so there’s no reason why you can’t. But don’t expect to get the same crop levels.
Squashes, how to grow
Q. Everyone seems to be growing squashes. How do you grow them, and what do you do with them when you’ve got them?
A. Squashes are good fun. They’re one of those nice plants that encourage children to be introduced to gardening. And they’re dead easy, that’s the nice thing. If you can grow a courgette, you can grow a squash, and I haven’t met anybody yet who can’t grow a courgette. You can buy squash seed in any garden centre and they come in all sorts of shapes and sizes: usually you can buy a packet of mixed seed and when you look at the front of the packet they look like the weirdest things you’ve ever seen. If you want squashes that you can actually use then I would generally recommend that you go for the Butternut squash, that’s probably my favourite of all the squashes, best flavour, and it roasts or makes fantastic soup.
The ornamental ones are brilliant – they’re really good fun, you can buy a packet of seed, they’ll so very easily either into a seedtray or you can sow them into individual pots. Again, it’s quite useful if you’ve got several children doing it or even a school doing it. Each child can sow one seed and plant their own out. As for planting them out, you can do several different things. You can either plant them out as you would a traditional American pumpking patch so you dedicate a whole area of the garden to them. You can make a squash trellis, if you so fancy. It’s rather like making a runner bean row, so what you would do is you would arch the canes up over and you train your squashes up the canes instead of letting them scramble across the floor – you have these really weird and wonderful squashes all hanging down. Some people will actually support them in stockings or nets or tights or whatever, to hold them up because they can get quite heavy. Melons can be grown traditionally like that, as well.
But you don’t have to go to anything as fancy as that: you can just plant them out into the garden, give them some slug protection to start with and once they’ve started there’s very little stopping them, they’ll get quite enthusiastic and you get stacks and stacks of these brilliant squashes growing away. You can get ones called Turk’s Cap squashes – they all have different, wonderfully exotic names.
Once they start to ripen – and you’ll know they’re ripening because they turn beautiful orange, reds and yellows of autumn colours – pick them and let the stems dry off. Normally I would look at picking them and, rather like you’d do with your onions, rest them on some netting or something outside in the sunshine. But they need to be stored cool and dry if you want to keep them for use in the winter, assuming that you’ve planted an edible variety. But a lot of people will use them for purely ornamental purposes – rather like when you get all these fantastic pumpkins for Hallowe’en Night – it’s very much the same time of year when all your squashes are becoming ready. A lot of places will put on fantastic displays of different squashes.
With most squashes, the flesh is edible, but rather like pumpkins they have the taste of what you do with them than of themselves. They’re best slow-roasted and then used in a soup or something of that nature – then they’re fantastic, wonderful fillers. They’re very nutritious and quickly fill you up: so they’re great if you’re on a diet but as I say, they mainly taste of what you cook them with than of themselves, I’m afraid! Sometimes you feel you need a pick-axe to get into them!
Succulents for a hot garden
Q. Can you suggest succulents for planting in a hot garden with lots of paving?
A. It does sound like you’ve got the ideal garden. There are a lot of succulents that you can grow. It would be useful to know if you’re frost-free, and probably for the benefit of this answer I’m going to assume that you are and that you’re coastal. So the things you want to look for are Agaves – prickly, vicious little souls so don’t put them right on the edge of the path! – but very impressive, very architectural. Echeverias which are, basically the House Leek but there are some superb varieties around, some really lovely named forms and they’re very lovely, they’re low-growing, great between paving, look excellent. Aeoniums which are very reminiscent of Mediterranean gardens I suppose: they look like House Leeks on a stick. You can get green ones, which are Aeonium arborium, but you can get the lovely deep purple ones which are called ‘Schwarzkopf’, also goes under the name of ‘Arnold Schwarzkopf’, which is gorgeous and big and juicy and succulent – they’ll do very well indeed.
Other plants which will give you that ‘succulent look’ without having to go down the Cactus root (which certainly wild horses wouldn’t drive me to!), I would look at things like Plectranthus which have quite thick, fleshy grey, hairy leaves: they look fantastic, lovely lush leaves on them. Also, some of the big-leaved Senecios, now known as Brachyglottis (which isn’t any easier!): lovely big silver-leafed forms of those, they look really handsome in that style of garden. Also have a look at the Coprosma: Coprosma ‘Pride’has a fantastic glossy leaf: the leaf in itself is about an inch-and-a-half long and maybe an inch wide, a variegated leaf that’s so shiny, so glossy you’d think someone had been out there with leaf polish, and it’s quite a thick, fleshy leaf again, so it gives you that really nice effect. Also, have a look at the Crassulas, there are some quite hardy forms of Crassula around, which are fleshy leaved in themselves. Lampranthus, which is the posh name for the perennial Mesembryanthemum, make wonderful sprawling carpets, very fleshy and milky with ‘Day-Glo’ colour when the flowers are out. Also, the Aloes are quite good: they give wonderful spikes of flowers – well, they look like a sort of Mediterranean Red Hot Poker which I always think looks very good. Fascicularia bicolor is another plant I would include. Strictly speaking, is it succulent? I don’t know but it’s certainly got the Mediterranean look – huge rosettes that look like a pineapple coming out, with that lovely red centre on them and blue flowers right in the middle, gorgeous things. Hopefully, that’ll give you enough to go on!
Sudden Oak death, detection and treatment
Q. does one recognise Sudden Oak Death? And what should I do if I find it in my garden?
A. Sudden Oak Death, or Phythophthora ramorum which is the botanical name for it, is difficult to recognise because many of the symptoms are so similar to other diseases which affect plants. Some of them are: spotting on the leaves and the tips of the leaves tend to go black and die back. The only way it can be correctly identified is in fact in the laboratory. The plants most prone to it in your garden are Rhododendrons, Camellias and Viburnums, although in fact the host list is really huge and for the full list you can look at the DEFRA website where they show you the entire list of plants that are susceptible. If you do have a confirmation of Sudden Oak Death, there is only one action and that is compete destruction of the affected plant; and you need to do that by burning foliage, stems and top, and digging up and removing the root ball and taking it away to deep land-fill. Hygiene is critical and absolutely paramount.
Summer fruit, suggestions for
Q. Please can you suggest some berries to grow for summer fruit.
A. Summer fruiting berries are probably my favourite bit of a vegetable garden. Gooseberries obviously come quite early, so ignoring those you are mostly looking at members of the Rubus family. This includes raspberries - if you haven't tried the autumn-fruiting varieties like 'Autumn Bliss' I would strongly recommend that you do so. As for blackberries - Himalayan Giant is vigorous, very heavy cropping and damn prickly, so only suitable for a larger space. 'Oregon Thornless' is a little better behaved. Loganberries are a tarter fruit, but they make outstanding preserves. Tayberries, which are a cross between blackberries and raspberries, have a milder flavour but crop well. One other group of plants to consider would be Blueberries, but you must have either a very acid soil or they can be successfully grown in pots as long as you only water them with rainwater.
The last one I would mention is the Mulberry Tree - delicious, with an interesting method of crop collection. Once the berries are ripe you need to spread some old sheets under the tree as the ripe fruits will fall on a daily basis: it's long-winded but well worth it!
Q. I like Sycamores, and I'd like to grow a hedge of them.
A. Sycamore makes an extremely good hedging plant, so long as you're prepared for it to get bigger. You can coppice it annually or every two years . Or if you want to do something a little bit more fancy, you can copy a method I recently saw at Highgrove, which was to weave the flexible year-old growth into a hedge which resembled a Celtic knot border. Rather than cutting and laying, you bend the branches and weave them into the knot effect. It is best done just before they come into leaf in March.
Tomatoes, choosing varieties
Q. Could you suggest some really nice Tomato varieties and tell me how and when to sow them?
A. Tomatoes, in a sense, are best planted out in the spring unless you are somewhere with very much higher light-levels. Commercially, to grow tomatoes all the year round in this country, you’d need to use artificial light, so I would not recommend it. But to give them an early start, you could certainly sow tomato seeds at the end of January or beginning of February. Start planting your tomatoes into a heated greenhouse or heated tunnel at the end of March going into April, but they will need frost protection for quite a while, depending on where you live. If you wanted to plant them out into a tunnel then you could grow them on in big pots until they’re ready to plant out in their final situation.
Tree and shrub cuttings in July
Q Can you suggest tree and shrub cuttings which I can take now?
A.. Virtually all shrubs are suitable for cutting material now, as they are best treated as semi-ripe cuttings. Tender perennials such as Fuchsias and Geraniums (Pelargoniums) will provide a wealth of cutting material now and free babies for next year. Heel cuttings are a matter of personal preference, and professionally is not a system we use very often. Most cuttings are better trimmed above the heel and below a leaf joint.
Trickle irrigation systems
Q. Can you tell me how to use a trickle irrigation system in a greenhouse or polytunnel?
A.Trickle irrigation comes in two main forms. One is a sort of leakey hose, which is generally used outdoors: you can use it for hedges, for vegetable patches and anywhere that you like really – it will suit those sorts of situations very well. I’ve used it very successfully for establishing a hedge in a dry area where the plants were going to be under quite a considerable amount of stress. But indoors, in a conservatory or greenhouse, you can use a form of drip irrigation. What you have is a more-or-less continuous length of hose, and you stab tiny little capillary holes into it at intervals convenient to you; and it has a dripper on the end which you stick into the pot or wherever you want to water. When you turn the water on, it comes out all over the place and does your watering for you – it’s a wonderful system. I think they’re used very often for hanging baskets and tubs and things: pubs and hotels have stacks and stacks of them and no-one is going to come out and water them by hand, so they just plug the hose in and turn it on! You turn it on when you need it: an hour of irrigation will give a lot of water. You can buy a kit for that sort of thing very easily; and places that sell a lot of irrigation equipment will normally have a basic trickle irrigation system without too much effort. It’s quite easy to do – it sounds more complicated than it is. Really, all you need is a connection on one end of the hose to plug on to your tap, and off you go. If you’re not sure how much it will run, then put the tap on and put one of the dippers in a jamjar and leave it on for an hour and see how much water you’ve got in the jar.
Vegetables for winter use
Q. Please can you suggest vegetables which will last through the winter?
Vines, how to grow them
Q. How do I start growing vines?
Vine Weevils, control
Q. What do Vine Weevils look like? What should I watch out for? And what can I do about it if I've got them?
A. Vine Weevil are the bane of gardeners'lives! The grub which causes the damage is approximately half an inch long, creamy white with a very distinctive dark brown head. You'll generally know you've got them when your plant turns up its toes, especially in pot grown plants. However you can find them outside in gardens particularly around certain perennials which they love - Heucheras, Astilbes and Primulas all seem to be especially popular with them. If you find evidence of these little delights you have two options. One is to treat the soil with either chemical or biological control: the chemical option is called Provado, or you can use a biological control available from Just Green. The alternative is to wash off the soil and replant in fresh compost.
Water, preventing run-off
Q. Is there any way of stopping water running off plants in pots in the greenhouse – or outside in summer – before the plants have had time to absorb it? A lot of water is wasted.
A.The only sensible way to save water that runs out of pots when you’re watering them is to stand the pots in saucers. In the greenhouse, you can get big trays – bench trays – which you can stand your plants in, so that you can water them that way. Anything the pots stand in will act as a collector.
Weather, protection in bad weather
Q. When the weather forecast announces that we’re going to have a deep freeze, what plants should one do something about outdoors? What can be done to protect them from, say, a biting east wind?
A.The plants most at risk are those that would be classed as half-hardy or tender perennials, and particularly those that are evergreen, where the foliage is still up and susceptible to a cold wind and/or frost. Also, plants that are in pots are vulnerable, because the frost can penetrate all around the root ball, whereas if a plant is in the ground it can only penetrate from the top down, so underneath in the soil the plants have the effect of a duvet sitting on top of them. Things like Pelargoniums, Fuschias, tender varieties – that sort of thing should already be in greenhouses or conservatories. They don’t have to be really warm, they just have to be frost-free. So if you’ve got plants in the garden that you’re worried about, if they’re in the ground a good mulch will help to protect them. And if they’re in pots, I suggest you use some bubble plastic and wrap the pots up in the bubble plastic (not the plants), and that will make a big, big difference to protecting the pots and the contents.
And the other thing to watch out for are evergreens because the foliage will dessicate, particularly in cold, easterly winds which will literally suck the life out of a plant because the foliage will dehydrate; and a lot of people forget that the plant can’t take up moisture if the roots are frozen, so it’s important to water them, particularly, or best, at the warmest part of the day when they can actually take up the moisture. As for wrapping up tender plants, this is something I’m very ambivalent about. Some people wrap tree ferns and palm trees over the plant – a lot of people wrap them and leave them wrapped all winter, and that is seriously bad news! Wrap a plant when it needs to be wrapped – and then unwrap it when the sun comes out again, and let it breathe, and that way you’ll avoid getting disease problems. And also remember, if you put horticultural fleece over something, if it’s resting on top of the foliage the frost will go straight through the fleece and still get the foliage. You need to have somes ticks or something underneath, to make sure the fleece is draped over the sticks and ideally not actually resting on the foliage.
Willows, can I move them?
Q. Is it possible to move a line of willows: they’re four foot high, planted with the aim of growing firewood, but now they’re in the way.
A. This depends really on how old they are and how long they’ve been where they are, because it’s not ideal to move them when – for a willow – they’ve been there for probably more than three to four years, I suppose. But then, again, it depends on how the willow has been grown: is it only four foot because it’s a dwarf-growing variety, or is it only that tall because it’s been pruned back to keep it under control? So you’ll need to establish how long it’s actually been there, I think that’s probably more important a criterion than its actual size at the moment. I would say that if it’s been there for more than three to four years, moving it is running a big risk of giving it a severe check, because they put on root so quickly. But if it’s one that grows up to four foot every year and gets pollarded back, bear in mind that you can take the stems as unrooted cuttings and plant these as an ‘insurance policy’ before you then attempt to move the plant, so that’ll work quite nicely as well. And willows are quite forgiving, if they’re the ones that grow rapidly (for example, one of the firewood types), you can more or less chop the root off them and they will grow – but if it’s one of the dwarf, bushy ones then I would say, probably it wouldn’t be safe to move it.
Q. Can you give me some advice about constructing artificial windbreaks?
The curious thing about windbreaks for plants is that they do more harm than good if they are solid. An ideal windbreak should allow the wind to be filtered rather than stopped dead. So if you cannot plant a hedge, I would recommend either “hit or miss” fencing or trellis work which offers approximately 50% filtration. The reason for this is that a solid wall will create a back flow of wind as it whizzes over the top. If a fence merely filters the wind the plants on the leeside will get shelter without unexpected down-draughts. If you want to make any form of windbreak fence, always use either tanalised softwood timber, or hardwood. Any form of metal mesh fencing should be galvanised. Be aware that plastic has a finite life.
Weather, protecting plants in bad weather
Q. When there's a forecast of severe weather, which plants should I try to protect and how?
A. The plants most at risk are those that would be classed as half-hardy or tender perennials, and particularly those that are evergreen, where the foliage is still up and susceptible to a cold wind and/or frost. Also, plants that are in pots are vulnerable, because the frost can penetrate all around the root ball, whereas if a plant is in the ground it can only penetrate from the top down, so underneath in the soil the plants have the effect of a duvet sitting on top of them. Things like Pelargoniums, Fuschias, tender varieties – that sort of thing should already be in greenhouses or conservatories. They don’t have to be really warm, they just have to be frost-free. So if you’ve got plants in the garden that you’re worried about, if they’re in the ground a good mulch will help to protect them. And if they’re in pots, I suggest you use some bubble plastic and wrap the pots up in the bubble plastic (not the plants), and that will make a big, big difference to protecting the pots and the contents.
The other thing to watch out for are evergreens because the foliage will dessicate, particularly in cold, easterly winds which will literally suck the life out of a plant because the foliage will dehydrate; and a lot of people forget that the plant can’t take up moisture if the roots are frozen, so it’s important to water them, particularly, or best, at the warmest part of the day when they can actually take up the moisture. As for wrapping up tender plants, this is something I’m very ambivalent about. Some people wrap tree ferns and palm trees over the plant – a lot of people wrap them and leave them wrapped all winter, and that is seriously bad news! Wrap a plant when it needs to be wrapped – and then unwrap it when the sun comes out again, and let it breathe, and that way you’ll avoid getting disease problems. And also remember, if you put horticultural fleece over something, if it’s resting on top of the foliage the frost will go straight through the fleece and still get the foliage. You need to have some sticks or something underneath, to make sure the fleece is draped over the sticks and ideally not actually resting on the foliage.
Wet ground, how to improve drainage
Q. How can I improve wet ground when it’s in the way?
A. Wet areas in the garden are very difficult. It will depend on whether it’s a large wet area because of the way the land lies, or whether this is smaller pockets of wet ground which need to be dealt with. The crux of the issue is drainage. If the wet patch is near the base of the garden, you can’t drain the water away. What you need to do is a two-fold attack: if you want to plant the area and you’re looking at plants that won’t tolerate a fairly damp soil, what you need to do is raise the soil level by bringing soil from other areas of the garden; that should raise it up so that you’re taking it away from the water table. At the same time you need to incorporate a lot of grit or gravel into the ground to try to improve the drainage. But if you’re talking about a point at which you’re at the water table, you can put as much gravel in there as you like, you’re not going to get rid of the water. Now, if the wet patch has been caused by compaction, then you can look at digging up the patch – dig up the area and see if you can get through the compaction and help the water to drain away. But it’s difficult to give a definitive answer, because it will depend very much on what the cause of the water is: find the cause and it’s easier to find a solution.
Winter Heliotrope, how to remove
Q. We have an ever increasing problem with Winter Heliotrope, Petasites fragrans. It was delivered in a load of topsoil which has been used to fill a wall as well as to top up other areas. Can you offer any advice on how to combat this plant? I have noticed that it is spreading throughout Cornwall in a similar fashion to Japanese Knotweed.
Go back and hit your topsoil supplier! Unfortunately, the damage is already done. The only way you’re going to control it is to use a Glyphosate-based weedkiller like ‘Roundup’ or a systemic weedkiller, but Roundup is the one I would normally recommend. And you’re going to have to keep hitting it. Now is a pretty good time to do it: it’s more or less finished flowering and leaf production is in full swing. Hit it now, you may have to hit it again later on this summer before it starts to die back. You won’t get it all in the first year, so don’t think you’re going to. You’re just going to have to keep at it. The biggest problem is where you’ve got it coming up through other plants that you want to keep: you have to bear in mind that the weedkiller will kill anything green it touches, so be very careful what you do it with.
For those who haven't met this plant yet, it has a round leaf about the size of your hand with your fingers spread. As for the flower, imagine a Bergenia flower spike only shorter: it has spikes rather than rounded petals, and it’s a very pale, dirty mauve colour. It’s groundcover but it is very, very invasive.
It should be on the Notifiable Weeds list as far as I’m concerned – it’s a real pest. You see it out in the hedgerows, where people have tossed it away and it just smothers the existing wildlife. If you get it in the garden, it’s a nightmare – it loves cultivated soil and just goes rampant.
Winter flowering shrubs
Q.Please can you recommend some shrubs that will flower in the depths of winter?
Midwinter is a lovely time of year to get extra colour in the garden, and there are many shrubs to fill that gap. Hammamelis has either yellow, copper or red flowers which look like saffron growing on trees. Many Viburnum varieties flower in the winter. Corylopsis pauciflora has delicate, cowslip-like flowers. Ribes laurifolium is a handsome flowering currant. Rhododendron "Christmas Cheer" doesn't always make it for Christmas but is usually there for January. Consider also many of the early-flowering Camellias (especially the Sasanqua varieties which are also delicately perfumed), Mahonias with their lovely lily-of-the-valley scent, and Bergenias with their evergreen foliage and spikes of cheerful coral-pink flowers.
Wood ash, using as fertiliser
Q. Wood ash: is it a good idea to spread it on the vegetable patch?
A. Yes, wood ash is fine as long as it is just wood ash. If it’s ash from a fire that burns wood and coal, then no, I wouldn’t recommend it. Pure wood ash is often used to sweeten compost heaps and you can mix it in with that; you can spread it on your garden or you can chuck it on to the vegetable plot. It’s like all these things, it’s good in moderation, not good if you’re spreading it inches thick. If you’ve got an awful lot of wood ash, then store it up somewhere, let the rainwater run through it and then you can use it on the garden as and when you want it.