Anticipating the Spring: planting trees, part II

Tracy Wilson chooses more trees and shrubs to plant this winter that will stand up to salt gales

2nd October 2006

This week I am looking at the ‘grey zone’, if you like, between shrubs and trees. When does one cease to become a shrub and become a tree? You’ll still find trees of which some people might say ‘Oh, that’s only a shrub in my garden’ and it might have something to do with the 90mph winds which sweep across their garden! You're always going to get somebody who differs with you.

When it comes to trees for coastal gardens, you’ve got to bear in mind that if you look around most wild coastal situations you get very few trees, and most of those have acclimatised themselves to those conditions by effectively becoming shrubs or hedges: in other words what they’re doing is holding each other up. Where you see wooded areas in that sort of a situation the first row of trees are looking pretty sad and battered but they’re offering protection to the next row of trees which are looking less sad and battered, and so it goes on as more protection is offered. Normally, if you grow any tree in isolation in an exposed coastal situation, it’s not exactly asking for trouble but you’re certainly going to be putting that tree under greater stress and strain, so think about it when you are planting. If you have a very exposed situation, could you plant three instead of one, or plant five instead of three? Give it some friends to hold its hands – in some respects they’re no different to people, and benefit from a little coddling along the road sometimes.

So, which trees do you need to look at? They divide broadly into evergreens and deciduous. Again, as a rough rule of thumb, deciduous trees blossom far better because there’s nothing on them to get damaged in the winter: that might sound strangely obvious, but if you think about the majority of bad weather which we get, it’s normally between (at least theoretically) November and March. The majority of deciduous trees are dormant then and you haven’t got a major problem to deal with.

Let's look at the deciduous ones first of all. At this point I’ll divide again and we’ll look at utility windbreak trees and then the slightly more ornamental trees. In the ‘utility windbreak’ category come the trees that most people think of as boring. That’s when you look at things like Sycamore, which seems to be virtually indestructible: I’m not going to say it looks pretty on the coast because it will still get windburn. The same applies for trees as anything else – what you’re looking for are ones that will tolerate the salt. Very few trees are going to actually thrive on the salt and Sycamore will, unfortunately, get burnt by the summer gales and look pretty untidy – but, it still grows – it grows like stink and it will filter the winds for other things. Ash ( Fraxinus family) is a very good coastal tree. Now these I think are slightly more attractive, I like the foliage which is slightly more finger-like and doesn’t seem to get the same damage as it seems to allow the wind to filter through it better. Whilst this is a fairly brittle tree, the Sycamore has more of an inclination towards bending. Ash is a handsome, fast-growing tree and good for providing that initial shelter.

I would also be tempted to consider the Alders but I would only recommend them if you have got a site that doesn’t dry up in the summer – it doesn’t have to be boggy-wet, just somewhere that doesn’t dry out a lot. In particular the Italian Alder is an exceptionally attractive variety: the leaves are apple-green and glossy, and going into the winter it holds its leaves longer than other varieties. All the Alders are very vigorous, they all have very pretty catkins on them in the spring. They’re quick, they’re cheap, they’re easy. You can plant them to give yourself a very quick screen and then you can fell them without feeling too unhappy. You can take out, say, two out of three and allow that third one to grow on. In years to come you could take maybe one out of two left whilst you’re putting more attractive trees on the sheltered side of it. They do make a very good windbreak tree and in fact they’re one that is very often used in fuel production, so if you’ve got an open fire you can fell them with a clean conscience because you know you’re not wasting the wood, you’re completing the Carbon Cycle if you’re using the timber up that you felled. So they’re a very good group to look at.

I’d also look at the Whitebeams, amongst the Sorbus family. Some people would go for the ordinary Sorbus as well but I wouldn’t put them as my first line of defence as they do tend to burn. But the Whitebeam group, which is the Sorbus aria and its varieties, does quite well on the coast. The silvery leaf, like a lot of silver-leaved plants, will tolerate salt winds much better: it’s the oval-leaved one which you often see, shaped like a kiddy’s lollypop tree, which you see in motorway service car parks. They do set quite nice clusters of berries – not the big, showy berries that you expect to see on ordinary Rowan, but fairly pretty trees, nevertheless. Sorbus intermedia, which is the Swedish Whitebeam, is another very good one for coastal planting, slightly slower than the ordinary S. aria and probably marginally tougher, I would say, if I had to chose over them.

Then you get down to the ‘Is it a tree? Is it a shrub?’ group of trees, into which I put Thorns. Crataegus monogyna, which is the traditional British Quickthorn or May Blossom, is rarely seen as a proper tree, certainly in Cornwall. But it will grow as a proper tree if you take a single stem up and allow it to develop. Mostly we see them as hedgerow trees in this county. You may know the Glastonbury Thorn which is a big, handsome Thorn tree. So there are good examples around and it’s always fun to try them. In fact, we’ve got one at the nursery which we’re trying to grow: it's a selected form and has been developed by some brothers in Hull. They’ve chosen this variety as being particularly strong and vigorous so we’re hoping that we can train it to come up as a half-standard tree. The ordinary, common Thorn – Crataegus monogyna – is a good one to look at. A particular favourite of mine would be Crataegus prunifolia which I think is a particularly pretty variety: it’s got an oval leaf, quite glossy, and it holds it leaves well into the autumn and it will then go reds and oranges before it drops. It also sets quite big, handsome red haws on it, so that’s a good variety. Also of course there is Prunus spinosa – Blackthorn or Sloe. It's very rarely that you’ll see a Sloe tree as such, you’ll see a Sloe shrub that’s made tree-like proportions maybe, but it’s generally multi-stemmed and what most people think of as a ‘hedgey’ type of tree. So they’d be my main choices on the amenity ones.

Of the ornamental trees, you could look at the same families and pick some of the ornamental ones from amongst them, but there are some others that I would add to the list. For instance, I would also consider Crab Apples – the Malus family – those ones have beautiful blossom. The advantage of the Malus over, for example, the Prunus ‘Japanese Cherries’ is that the blossom doesn’t come out just when we get the first spring gale: don’t ask me why, but it tends to just miss it! Crab Apples generally flower just a little bit later than the Japanese Cherries, they don’t seem to get snatched from the tree in quite the same way which is an advantag. You’ve got a choice of white, pink and red blossoms and you get the big bonus of a really lovely autumn fruit, which at this time of year (we’ve just had our Tree Week) and the fruit on some of them is just dripping, masses and masses of fruit set this year. So it really does give you another seasonal interest with the tree. You do have to think about that to get value for money.

Now back to the shrubs. Eucalyptus can be kept pruned as a shrub or you can let it grow as a tree. Amongst others in that category, I would also include Euonymus: a lot of people are very familiar with the evergreen Euonymus as a groundcover shrub, very versatile. The deciduous Euonymus like E. elatus and E. europeus (especially E. europeus ‘Red Cascade’) have fabulous autumn colours and lovely winged fruit which are very strange because the fruit itself is usually pink and when it splits the seed which hangs down below it is bright orange. It’s a very weird colour combination but it works – it’s very striking and makes for a very attractive plant. Then there are the Eucryphias, but you’ve got to be a little bit careful with those ones in exposed coastal situations. Again, it’s a shrub or it’s a tree, but it would need some shelter in a coastal garden.

One plant, which most of us think of as a shrub and which will take anything which the sea can throw at it, is the Arbutus or Strawberry Tree. I sold one this morning which was absolutely pickled in lovely round fruits which somebody in a slightly hazey state of mind might mistake for a strawberry. It has rather knobbly fruit which remind me more of a Lychee, I think, than a strawberry. They start off yellow and then go bright red when they’re ripe. They hang off the tree, almost like Christmas Tree decorations. They’re about the size of a Lychee and that is the best description I can give you. The foliage is evergreen and it gets this lovely peeling bark as the tree matures. It is very, very resistant to coastal exposure so it’s a cracking coastal tree. It’s not planted enough! Its flowers are white, reminiscent of Lily-of-the-Valley or Pieris flowers, although there’s no scent with them, unfortunately. There are some very good varieties: ‘marina’ is a fairly new, quite vigorous variety and worth looking out for. But I’ve used A. unedo and A. unedo ‘rubra’ and A. anrachnoides which are all extremely good varieties and would suit most sizes of garden: they take a long time to get big and they’re very amenable to being pruned which is always a useful commodity for them. The fruit isn’t poisonous but it’s totally and utterly bland. The birds will take them when they’ve fallen. We were looking at one this morning, thinking ‘shall we or shan’t we?’ It's not on the poisons list and it’s not toxic. I should just imagine it’s a bit ‘yeuch’ but I’ve never actually tried it.

Then there are the Myrtles. They’re another one which are in the same group as Arbutus in that it’s a shrub with ‘tree-like aspirations’. Eventually it has these beautiful stems with an almost cinnamon-like bark (a lot of these plants do: people don’t realise). And of course Myrtle has an evergreen foliage but with beautiful white, scented flowers. In a hot, sunny position it will set black fruit on them which are fairly attractive.

So there’s quite a lot to whet the appetite when it comes to moving down from the ‘tree tree’ department to the ‘shrub tree’ department that would fit most people’s gardens. Cotoneasters, Cornus, Cytisus, Spartium – all of these ones in the right situation will become small trees, so it’s a matter of deciding really what sort of ultimate height you want, and the habit you want in the garden. Rather than saying, ‘I need a tree type tree’ do you want something that’s a little bit more feathery or graceful, or do you want space underneath, do you want to sit under it: what do you want to do with your tree? These are probably some of the first questions you want to ask yourself.

Tracy Wilson, 2006