Country & Garden: Good bone structure

THERE WAS a boy at my husband's school called "Greasy". I know nothing about him except what I have divined from his name, and the fact that he once wrote these deathless words in a biology essay: "Bones are to stop your arms floping into a blob." As the leaves finally come off the trees, and the herbaceous perennials in borders are cut back, many gardens are also in danger of floping into blobs. They need some bones to hold them up.

Good bone structure is as important in a garden as it is in a middle- aged woman, when the flesh first begins to sag. It can be made with what we call "hard landscaping" (paving, walling, steps, trellis, fencing and arches), but also with most evergreens, especially the tight-knit clippable ones, and those relatively few deciduous shrubs and trees with dense branches and sturdy stems.

Most deciduous plants, unfortunately, lose their shape when they lose their leaves and are inclined to degenerate into airy twigginess or blobby ground-covering. And this dormant period lasts almost half the year. They are the flesh that sags, and we need now to think how to plan our gardens so that the bone structure can show through in winter.

I am afraid it means some appreciation of the virtues of geometry, another subject that may have stumped "Greasy". Garden-planning is partly about managing space, and that you do by defining it with, or carving it up into, geometric shapes. Straight lines, especially squares and rectangles, best create a "formal" effect but, for a "semi-formal" atmosphere, curves, parabolas and circles can be employed as well, or instead. Both horizontal and vertical planes need to be considered. Vertical hard structures or strong plantings will give you light and shadow in winter sunshine, and their visual impact will be enhanced when their shapes are dusted with frost or light snow. The pattern remains throughout the winter; in fact the absence of summer flowers and other clutter brings them more starkly into relief; except when there is heavy snowfall, of course, in which case the pristine beauty of a white blanket more than compensates for any temporary loss of definition.

"Hard landscaping" is plainly important for creating the garden's skeleton, but so, too, are plants, especially hedging, which is capable of making almost any shape you like. This is particularly true if you use small plants, such as dwarf box - Buxus sempervirens `Suffruticosa', or Buxus microphylla - which have tiny leaves and can be planted very close together. It is no accident that dwarf box has, for centuries, been the preferred plant for parterres and knot gardens, in which intricate shapes were realised on the ground, for the benefit of people looking down on them from above.

For a taller hedge, yew is desirable - except where the soil is badly drained, or for a boundary hedge next to a field where there are livestock, for all parts of this plant, with the exception of the red "arils" around the seeds, are poisonous. If you would prefer to use another conifer, but are terrified, rightly, of Leyland cypress, I suggest you use either Chamaecyparis lawsoniana `Green Hedger' or Thuja plicata `Atrovirens'. Other good evergreens are hollies (ilex) and Osmanthus delavayi. The important thing to remember when buying plants for hedging is that they should all be propagated from the same clone, so that they are identical. It is vital to ask before you buy.

Hedging need not be evergreen to retain its thick-knit structure in winter: hornbeam (Carpinus betulus), and beech (Fagus sylvatica), are both sturdily structural and, if you trim these hedges in summer, the brown, dead leaves will not be shed in November, but will endure on the twigs until new ones emerge in April.

Structure can also be created in the garden using specimen evergreen trees and shrubs, though it is usually fatal to dot them about any old how, when they look like the too liberal use of exclamation marks on a page, distracting and unilluminating.They must have a purpose, guarding each side of an entrance, ending a vista or defining a space. The revival of interest in restrained topiary in recent years points to a greater understanding of its role in the winter garden, especially when plants are placed in pairs or as edging to paths and walkways.

This is an excellent time for planting deciduous hedging, but evergreens are best left until the spring; unless, that is, you have a light soil, you can find them on offer in containers and you can protect them adequately from desiccating winds with green, perforated polypropylene "windbreak material" fixed firmly to posts, not only for this winter but also for the next. Otherwise, spend the time this month preparing the soil well, by digging out a trench, filling it loosely with a mixture of soil and home-made compost or rotted manure, and leaving it to settle until April.

This sort of garden planting is absorbing, tense (because it is so important to get the measuring right) and physically tiring. However, though you may flope into a blob at the end of it, your garden certainly won't.

This photograph was taken from `The Garden in Winter' by Rosemary Verey (Frances Lincoln, pounds 25)