While the weather in the region where you live obviously forms the principle influence that climate has on what you can grow, sometimes aspects of your house and garden can create a local mini-climate, which can make a surprising difference to the plants which will thrive.
A range of factors contribute to this microclimate effect, from large things such as the garden’s location right down to smaller features like the position of a trellis. Understanding how microclimates work is the key not only to arranging your planting to suit the existing environment in your garden, but also to providing or adapting features to provide particular growing conditions.
Shelter, Shade and Orientation
The compass direction of the ground clearly affects the amount of sun it is likely to get as well as its exposure to wind and rain. Soils which face south generally warm up more quickly in spring and so may be useful in providing a display earlier in the year than other areas of the garden. If the house or garden has south-facing walls, these too can be used to grow climbers which might otherwise be too tender.
Not only do they offer the same benefit of ready sunshine as before, but they also will retain heat for a considerable period into the evening and night, making the local conditions much warmer than elsewhere. Taking this a little further, creating a small enclosed area beside such a wall by adding trellis-work or a pergola can set up a remarkably warm and sheltered microclimate, in which frost is seldom if ever seen and some quite surprising kinds of plants can be safely cultivated.
For plants which are more shade-loving, the areas under trees or beside hedges and fences can offer ideal conditions. However, it is important to be aware how the amount of shade available varies over the seasons with the changes in both angle of the sun and the state of foliage during the year and plant accordingly.
Wind and Water
Strong winds can be a serious problem, particularly for exposed sites, causing much damage to susceptible plants. The location and lie of the land are significant influences on how greatly this will affect any particular garden, with coastal or elevated sites often having little protection from the worst of any winds. Even in less extreme conditions, the layout of buildings in and around the garden can alter wind movement on a local level, either by acting as wind-breaks, or wind funnels – channelling the air into one direction.
This can be a particular problem in heavily built up areas, where the wind is directed between houses and may develop significant force and turbulence. Under these circumstances, the gardener has the choice of either avoiding planting in wind-swept zones entirely, or erecting some kind of suitable wind-break.
Location also has a major bearing on rainfall; land to the windward side of high ground will always tend to have more rain than a site on the leeward, while gardens sandwiched between high buildings will often be drier than more open neighbouring ones. Water within the garden too can provide a micro-clime effect; where water naturally collects in low lying areas, the soil may stay almost permanently wet and create perfect conditions for moisture-loving bog plants. Even around an intentionally constructed pond or bog garden, the slight additional humidity in its vicinity may alter the growing conditions for nearby plants – and sometimes even the smallest variation makes all the difference.
No two gardens, however close, are ever precisely the same and the conditions even within neighbouring plots can be quite startlingly different. Microclimates can be set up in the smallest of ways; even the lee of a rockery stone can provide enough shelter to improve the prospects for anything planted there, while fences and walls can change things enormously. Understanding the effects that localised microclimates can have opens the way to growing the widest range of plants and in the most imaginative ways – providing gardeners with the best possible opportunity to have exactly the sort of garden they really want.