Going Grey

The UK has over 11000 miles of coastline. Over 19000 if you include the islands, and an even bigger number in the metric equivalent. So, though I do not have the demographic knowledge to produce statistics, I feel quite confident in assuming that a significant part of the UK’s population lives fairly near the coast. But since I never trust statistics anyway, I’m happy to proceed on instinct.

I grew up and got into gardening in an era when not only was gardening uncool, but the term “uncool” hadn’t even been invented. The current plethora of gardening books was barely a twinkle in a publishers eye. Gardening magazines were few, and most featured Percy Thrower wearing a tie. I seem to remember it was always a black tie, but I could be confusing this memory with black and white telly, where all the snooker balls were grey.

A myth was spawned in those days.

A myth perpetrated by many respectable institutions, not least the RHS. The RHS A-Z is one of my most thumbed tomes. It is often my first port of call, though not the only one. I regard it with great respect, and will continue to do so, despite it’s obsession with frost. The myth is that frost is the gardener’s greatest enemy. Plants are classified according to frost-hardiness, with little mention of tolerance to wind.

But if your plot is on the Pennines, your garden is in Grimsby, your allotment is in Argyll or your smallholding is in Shetland, you don’t need me to tell you that your greatest problem is the wind. And coastal areas have an additional complication. Coastal areas only experience moderate frosts, but salt is as much of a threat as wind. Wind and salt are the enemies of all gardeners who live and work around those 19000 miles of coastline.

When a popular TV gardening programme tells me to mulch my cordyline with bracken fronds to protect the roots from frost, I feel the need to stroke the dog for his therapeutic value. Firstly, I’m concerned for my investment. I bought a new telly recently, and a welly through the screen would have serious financial implications. Then, secondly, being dog-strokingly calmed, I can consider objectively the other aspects of my annoyance.

My cordyline doesn’t need protecting from frost. Given the temperature recordings over many years for my coastal location, I can confidently expect that the temperature will not drop to the point where the cordyline is at threat. However, it is all academic, since I cannot actually grow a cordyline here, because the wind shrivels it to a desiccated skeleton. Frost is not my main problem.

In Plockton, on the west coast of Scotland, the palm trees which line the streets are captured by every visiting camera, and were piddled on by the wee dog in Hamish MacBeth. They are living proof that a coastal climate, even on a latitude north of Moscow, can support plants classified as tender.

Fuchsia is a predominant hedging plant on the island of Orkney. Phormiums take centre stage in the otherwise bland and predictable landscaping of a business park on the north coast of Scotland.

But all of the above, though they would succumb to hard frost, tolerate high winds and salt. In my book, that makes them hardy, even if they are not classified as such by the RHS. It’s all in the definition of hardiness, and one size does not fit all. A plant is hardy in some locations, and not in others. It may succumb to frost. It may also succumb to wind or salt. It cannot be classified as hardy simply because it has survived minus x degrees in a sheltered location.

Perhaps, particularly in our rapidly changing climate, the RHS and our nurserymen need to revise their criteria for determining hardiness. The current obsession with frost is becoming increasingly inappropriate.

Anyway, I’ve had my rant and I feel better for it. Time to get down to business. If like me, you have a problem with wind and salt rather than frost, where do you begin to create the shelter that your vegetables and less tolerant ornamentals need?

I could just make a list, but that wouldn’t help quite so much as giving you tips to assist you in recognising shrubs which are likely to be wind- and salt-tolerant. A plant is likely to tolerate salt laden winds if –

1. The leaves are grey and hairy, or grey and leathery
2. The leaves are dark green and fleshy
3. The leaves are grey, thin and hard
4. The leaves are green, thin and hard.

So instead of a list as long as your arm, you can browse around your local garden centre or nursery with just these four hints, and see what you find.

In category 1 would be Senecio, or specifically S. greyii (the clue is in the name), though the cultivar Sunshine is more commonly on offer. It is grey and hairy. Grey and leathery is Olearia, both O. macrodonta and O. haastii. The latter is often known as the Daisy Bush, and the clue this time is in the flowers. Macrodonta has holly-like leaves, and it particularly will tolerate all the salty wind you can throw at it.

The market leader in category 2 has to be Escallonia macrantha, although any of the Escallonias will do okay. Macrantha is the one with the large, dark green leaves, and is the least prone to wind and salt burn. A gardening client of mine recently played host to a friend of his, a professional gardener, who was making his first visit to the north coast of Scotland. “I don’t understand why you don’t use more Escallonia here,” I’m told he observed. Whereupon my client took him down into the garden, and showed him the series of E. macrantha hedges which I had not only planted three years previously, but had in fact grown from cuttings from one purchased plant. Smug? Me? Not at all. Green holly (not the variegated ones) also falls into this category, though probably only the native Ilex aquifolium is reasonably wind-tolerant. Salt is no problem, though. Some Berberis, notably B. julianae, B. darwinii, and B. stenophylla are worth a go, as are many of the Cotoneasters.

I confess I can only think of one candidate for category 3, but it merits having a category to itself, because I doubt if there is a better first line of defence against salty winds. The thin-grey-leaved Hippophae rhamnoides is better known as Sea Buckthorn. It can be a bit invasive, as it suckers freely, but when you are battling to establish a defence against a salt-laden north-westerly, suckering is a bonus. At least it is in the short term. And once the thicket is established, you can dig up the suckers and use them to begin the next phase of your defences. Hardy, vigorous, and a source of free plants – what more could you want? Okay then, how about the added bonus of berries which the birds love? Sea Buckthorn fully justifies a category of its own.

In category 4, green and thin suggests conifers, but beware. Most conifers hate salt. Many hate wind. One of the many bonuses of living where I do, is that Leylandii won’t grow. Many have tried, most have failed. No, the key word this time is not “grey” but “hard”. The usual hedging conifers like Leylandii, Thuja and even yew (Taxus) have soft foliage which shrivels away in a salty, windy winter. Only the hardy pines, like Pinus contorta (Lodgepole pine), will tolerate these conditions, and they will inevitably become distorted (or contorted, the clue is in the name) as the seaward side dies back. Think beyond conifers. Think gorse, perhaps. I know many of you will see gorse (Ulex europaeus) as a weed, to be grubbed up and removed. But as an outer windbreak, you’ll find few things hardier. And it provides that vital first line of shelter, allowing other plants to become established in its lea. It can be removed once the more user-friendly shrubs have a good hold. And don’t rule out broom. Cytisus may have softer foliage, it may be relatively short lived, and after a real wintry blast it will show signs of die-back. But it is an excellent nurse to other shrubs. And those with variations in flower colour are no less hardy than the common yellow version. It offers a bonus, too, especially for the kids. It is really easy to grow from seed. Just wait until the pods begin to burst, then collect and sow immediately. Don’t try to store it because it won’t keep. But collect seed from a plant with multi-coloured flowers, and see what you get. It doesn’t come true from seed, and most seedlings will revert to yellow. But persevere, pot them up and grow them on. You’ll get some surprising flower colours. And here’s a tip. Ignore the usual advice about selecting the strongest seedlings. In this case, select the weaker ones. They usually produce the most interesting colours. You see, creating shelter doesn’t have to be a chore. It can be fun, too!

And now to category 5. Yes, I know I didn’t do a category 5 above. It’s not a mistake. The four categories above cover shrubs. These criteria don’t always apply to trees, so category 5 is the wild card - a brief list of trees which will tolerate wind and salt.

Salix, most species. The Goat willow (S. caprea) is particularly good, and perhaps unsurprisingly it has greyish leaves, but S. alba and all its descendants and hybrids will serve you well. The willows like plenty moisture of course, and this can be an issue in coastal areas where the soil is often sandy and therefore free-draining. Try them anyway. They don’t read the textbooks, and are far more tolerant than they are given credit for. But cut them back ruthlessly annually, starting from year one. Your objective is a thicket of stems, not a few flagpoles.

Alnus. The common alder, like the willow, likes plenty moisture. But again, it is more tolerant than you may think. Treat it like the willow, and chop out the leader. It will grow as a bush, and provide much more effective shelter as a result. A. incana – the grey alder – is even more resilient in salty winds, and once more the clue is in the name.

Sorbus aria and intermedia, those lovely whitebeams. The native whitebeam (S. aria) is good, but the Swedish whitebeam (S. intermedia) is better. In fact, I would have to say that of all the trees at our disposal, the Swedish whitebeam is the one I would begin with, if I were starting from scratch with an open plot on an inhospitable coast. S. intermedia is the top of the tree, so to speak. And guess what? Check out the underside of its leaves. They are grey.

I didn’t plan that last one, it just happened. But what a great link back to the grey theme. Sometimes you spend sleepless nights working out themes. And sometimes you just get that break.

Got a salt and wind issue? Looking for windbreak plants? If it looks grey, trust it.

© Mike Clark 2007

Published in Organic Gardening January 2008