Winds needn't be your biggest problem if you learn how to tame them

Wind brings the weather. As I write, a northerly is slicing through the garden, hustling through the cracks and gaps (plenty of those) in the house. It's a sunny day and I'm at my desk in two shirts, a cashmere jersey and a fleece. If it wasn't for that nagging, rushing shake-down of the branches snagged by the wind I would think I was ill. Mercifully, the north winds are almost as rare for us as the bitter easterlies that we occasionally get in spring. On this west side of England our prevailing wind is a wet and warm westerly. Southern winds bring dry weather and the stench of concentrated turkey shit from the poultry factory at the end of the lane.

Wind is usually the biggest single influence on how a garden grows. One of the first things you should do when you take over a garden is to map the wind; not on paper, but in your head. Get to know exactly what the relationship is between your plot of ground and the prevailing winds. The shape of the wind is as important as its direction and strength. It can come in so many forms.

A wind flowing as straight as an arrow will tumble over walls and fences, crushing and flattening plants like a boisterous wave. A mild breeze can be funnelled down alleys and the gaps between houses and in the process become a rapier, bayonetting a few choice (and usually slightly tender) plants. We have all seen the wind pick up a pile of leaves and swirl them around like a spoon in a cup of tea. Wind bounces and rebounds off solid surfaces like a ball, hitting crazy angles and causing wierdly unguessable microclimates. What often surprises people is the damage that wind causes at the base of a wall because the force is directed down just as strongly as it is pushed up over the top.

I guess that wind is the gardener's biggest problem. I was about to write 'enemy', but it does have its virtues. A south wind is wonderfully effective at drying up soggy ground and a north or east wind scours the garden like a dose of salts. Not pleasant, but the garden comes out from it generally healthier. And the rare times when there is no wind at all are fine for a day if it is sunny, but then the air gets as stagnant and rank as a scummy pond. If there is no real wind then fungal diseases proliferate and air pollutants linger. Good ventilation is essential for plants, especially woody trees and shrubs such as apples and roses, and half of all pruning is to establish a good airflow through the branches. But to make that effective you need flowing air.

So what does wind do? We all think that it makes cold weather feel colder. But there are times when the lack of wind is disastrous to the gardener for precisely the opposite reason. If your garden is on a slope with a building or wall at the bottom, cold air will flow down the hill, meet the wall and eddy back up - exactly like water. Wind would help disperse that cold air and stop it collecting at the bottom of the slope. If your garden is at the bottom of a slope or in a natural basin then it is essential to design your shelter to let the wind in where you want it, to flow through and get out again.

Wind cools the air around plants as they grow, and in spring will often be sufficient to drop an otherwise mild day below the critical growing point of 6°C. In the past few years we have had weeks of just this situation, where the entire garden is locked in stasis by the dry wind. The lop-sided effect of wind-exposed trees is caused by the wind slowing the growth dramatically on the exposed side, while at the same time being absorbed so that the sheltered side grows normally.

We think of wind damage being a physical assault and conjure up images of cliff-top trees sliced diagonally by the wind, but by far the biggest problem from wind is its drying effect. Leaves dry exactly like a row of shirts on a washing line, and the stronger the wind the more plants dry out. Evergreens are particularly vulnerable to damage from wind in winter because they are constantly transpiring and losing water.

If there is a cold, dry wind blowing that water will not be replaced, and it is not uncommon for otherwise quite hardy plants, like box or holly, to die of winter drought, especially on roof gardens. This can happen very rapidly if the soil that they are in is frozen, as the roots will not be able to absorb any water at all. One of the best solutions in very cold dry weather is to spray the plants with water, which then freezes and forms a protective film around the leaves.

Wind also causes physical damage. Branches get broken and trees ripped up by the roots and hurled over. But even in violent storms the wind can be diffused, although I remember visiting some plantations after the storm of 1987 and all the exterior rank of trees remained standing while the interior ones - which they had been protecting -were flattened. This was because the outside ones had grown exposed to the wind and had developed stronger roots as a result. The moral of the story is to plant trees small and only stake them for the first year or two so that they can gradually develop their own wind-resistance. Wind will cause 'root rock' in young shrubs and herbaceous perennials if they are exposed or not planted firmly.

There is nothing that you can do about the wind itself, but if you know exactly how it behaves as it passes you and your garden then you can start to protect the site and, where it is unprotectable, adjust your planting so that you are not exposing the garden unnecessarily. A filter is much more effective than a solid barrier. The latter, by the way, is effective if your garden is on the leeward side of the wind, but only provides a shelter zone reaching a distance roughly twice the height of the wall. Beyond that the wind often comes down harder than ever.

The best and most usual filter is a hedge. An evergreen one is more solid but a thick deciduous one is often most effective of all in filtering the wind, absorbing and gently diluting its force. In a large garden, hedged divisions will create a web of barriers so that there are pockets of very protected areas within a larger, generally protected space. Hedges don't have to be tall - a low box, lavendar or santolina hedge will make a real difference to a herb garden, for instance.

Shrubs and trees are also very effective. When we moved into this site I planted a double row of fast growing poplars as a wind break and have just cut them down now that there job of protecting other plants is done. Best of all is a double-baffle of a line of trees with a belt of shrubs inside them. Wind breaks do not need to be permanent. Jerusalem artichokes or runner beans can be used to great effect at the edge of a veg garden during the growing season. I have seen wheat used in a garden as a temporary windbreak. I don't know how effective it was, but it looked great.

I have found that woven hurdles make the best temporary shelter, especially along a newly planted hedge. Hazel ones are best but willow are a reasonable substitute. Trellis also works well, especially if the spaces are small. Even more temporary is netting, but very effective.

The beneficial value of a windbreak can at times be outweighed by the shade that it casts. Tall trees and huge hedges around a small garden will cut out as much light as they do wind. Any barrier will create a lot of shade to its north, quite a lot to its east and some to the west. Any barrier will create more shade in every direction in winter than in summer. Common sense rules.

Plants for exposed gardens
No plant likes wind, but some are much better able to endure it than others. A good guide to the durability of a plant in wind is the thickness of its leaves. If they are very small, or spiny or waxy they will be much tougher. The following are good to absorb the wind and to protect less robust plants:

Trees Leyland cypress, holly, alder, willow, hawthorne, mountain ash
Hedges Hawthorne, hornbeam, leyland cypress (if you must) beech, thuya plicata holly
Shrubs Escallonia, rosa rugosa , berberis, elder such as sambucus 'Black Beauty'