The winter suns starts to gain some power in February and you can often feel the warmth, especially in still conditions. The days are getting longer and the angle of the sun gets higher every day, spotlighting the garden a little more sharply as the month progresses.

So it is one of the best months to appreciate the beauty of trees - whether it is winter blossom, textured bark, or the fine tracery of spidery branches.

Trees are not only beautiful. They add scale and they alter the dynamics in a garden, even in a small garden, as they cast their moving kaleidoscope pattern of light and shade on the ground.

They are an essential part of a woodland habitat too, where spring-flowering plants abound. Their branches give overhead shelter in winter. Their root system warms and drains the ground below allowing hellebores, wood anemones, miniature spring narcissi, pulmonarias and other woodlanders to flower earlier under their benign presence.

Trees also provide more diversity and pull in more insect, small animal and bird life and this is important in an age where green spaces are disappearing fast. My own new and very bare garden, which I started to plant about two years ago, was devoid of trees until last spring.

The woodlanders were performing well, but the whole area looked bland, rather like rice cooked without salt. Then I added my favourite tree - the winter-flowering cherry (Prunus x subhirtella Autumnalis') and the whole area came to life.

Trees should be always be sourced at specialist nurseries where the turnover is constant and the labelling correct. If you are planting in winter, you can buy cheaper bare-root trees. Although they start smaller, they often romp away more easily than container-grown trees. My containerised tree came from Nicholson's Nurseries, just south of Deddington (01869 340342/ www.nicholson-nuseries.co.uk).

The winter-flowering cherry is a tree I fell in love with in my early childhood. Several bounded the primary school playground close to the west London semi where I grew up.

On winter days when the sky was gunmetal grey I would chase blush-white confetti across the equally-grey tarmac, before looking up to see the fine-dark branches smattered with tiny flowers. They always reminded me of fine snowflakes in the wind.

There is a pinker one (called Autumnalis Rosea') and several pendulous forms but I enjoy pale blush-white flowers set against almost black branches. This is the only truly winter-flowering cherry and it rations its flowers over several months.

Those playground trees are still there 50 years on, despite the Heathrow traffic above, so this tree is a tough resister of pollution. But it is also glorious in the country too.

The first lesson when planting a tree is to choose one to match your setting. A variegated sycamore, or a heavily-frilled cherry, or a red-leaved beech though fine on a suburban road, will stand out like sore thumbs in a pastoral setting.

Many cherries make excellent flowering trees. Prunus mume, the Japanese apricot, usually bears single almond-scented flowers by the end of February, or earlier in sheltered gardens. Beni-shidare' is the most striking with strong, madder-pink flowers. Prunus mume is usually grafted below the branches so check the bumpy graft to make sure of its strength and soundness.

The bush-like, low-growing Prunus incisa Kojo-no-mai', a variety of Fuji cherry, produces an abundance of pale-pink flowers in March and it is possible to plant a low hedge of this, should you wish to. I use twiggy bush among dark hellebores.

One particular cherry from China, Prunus serrula, is grown for its shiny, mahogany bark, which is lined and marked horizontally. The sparse branches are covered with small, white flowers in late spring and, if you use pale foliage round this tree, it will shine out in the winter garden. It also casts a light shade and many plants happily thrive underneath.

Pale-barked trees can look stunning in winter sun and the Himalayan birches (Betula utilis) are among the best. Choosing one is like Blind Man's Bluff however, as the bark takes up to ten years to acquire its silver-white lustre. The widely-grown B. utilis var. jacquemontiiis variable.

Jermyns', Silver Shadow' and Doorenbos' are much more reliable. My own favourite has always been a variety of Erman's birch called B. ermanii Grayswood Hill'. It has creamy bark and large, serrated, green leaves that yellow in autumn.

Pale-stemmed birches can be grown as single specimens, or several can be grouped together, or there are also multi-stemmed trees which branch from the base.

Whichever you choose it is essential to plant something bright close to the trunk and a mass planting of early-flowering, bright-pink Cyclamen coum works really well because birches are surface-rooted and their close partners need to be drought-tolerant.

Snake-bark maples, which can be very challenging to grow, always look as though they have had an expensive paint treatment with silver-striations running at verticals. These are not trees for exposed sites and they often grow best as canopy plants tucked close to larger trees.

Acer davidii, from China, has smooth green bark lined in silver-white and there is a highly desirable form with maroon-toned bark called Serpentine' (available from Bluebell Nursery, 01530 413700/www.bluebellnursery.com).

There is also an American snake-bark maple called Acer pensylvanicum and one form, Erythrocladum', has candy-pink new wood marked with white. I have seen more hospital cases than healthy trees.

But help it as hand, for there is a robust, yellow-barked hybrid between the American and Chinese snake-bark maples - Acer x conspicuum. Phoenix' is a fine form.

But not all acers have smooth silver-lined wood. The Paperbark maple, Acer griseum has ragged, chestnut-brown bark which flakes and peels to reveal new cinnamon-toned bark beneath, and the leaves colour gloriously in autumn too. This tactile tree is among the best in winter sunshine.

So if you are looking at a boring garden, adding just one good tree will make all the difference.