Pruning should be the kindest cut of all.  There is much more to it than simply lopping dead  and diseased branches off trees and shrubs.  For years, that's what I thought it was all about:  wander, ponder and then hack the heck out  of whatever disturbs your eye. But pruning is a much  more subtle art.

It helps if we understand what nature is trying to do -- produce a healthy, vigorous, beautiful plant. The challenge for the gardener is to find ways to work with nature to achieve that goal. A key concept to grasp about pruning is that it is a way of redirecting nature's central energy. Sap flows up through trees and shrubs with immense vigor in spring, producing astonishing new growth. When you prune, you are directly interfering with that energy. A simple cut can send sap rushing in an entirely different direction. Cut the top off a tree and nature will respond by producing a dozen new tops, all fighting for dominance.

The pruning process is like playing  at being nature's traffic cop, stopping sap here, waving it on there, slowing it  down this sidestreet, allowing it to speed  unimpeded along this highway. It's no wonder once gardeners grasp  the creative potential in all this that they quickly move  on to doing topiary and espaliers,  pollarding and bleaching - all artistic refinements of the  basic pruning techniques. But pruning is more than a game. The main reason we step into our gardens this month to prune  trees and shrubs is not only to make  plants grow in pleasing shape and forms, but to finish off what winter didn't quite  complete - the removal of dead, diseased  and weak material that hinders  a plant's health and vitality.

PRUNING GUIDELINES There is no single, fits-all rule for pruning flowering shrubs. Each plant has to be treated individually, which means doing some homework to find out how the plant grows, when it flowers and whether it appreciates being pruned or not. Some guidelines:   ROSES The best time to prune most roses is when new growth is beginning in February. Moderate pruning, which involves cutting back stems by about half their length, is regarded as the safest approach, followed by harder pruning once buds break. The Royal National Rose Society in Britain recommends what it calls the Easy-Care Method. In this, the bush is cut to half its height. Dead and diseased stems are cut, but forget about the weak, twiggy stuff; under this method it is seen as inconsequential. Trials have shown the Easy-Care Method works perfectly well for the majority of roses. Climbing roses, however, need very little pruning.   CLEMATIS You have to know its blooming habit in order to know when and how to prune clematis. There are three basic groups: 1) Vigorous varieties (Jackmannii, The President, Tangutica, Ville De Lyon, Etoile Violette) that flower either in late spring, summer or the fall on new growth. Prune them close to the ground in February and March. 2) Varieties that flower in early spring (Jacqueline du Pre, Tetrarose, Blue Bird, Markham's Pink, Rosie O'Grady) on wood produced the previous year. The popular montana and alpina varieties fall into this category, as well as the highly scented C. armandii. Prune only to remove the weak or dead stuff. 3) Clematis that flower both on old and new growth (Nelly Moser, Barbara Jackman, Bees Jubilee and many others.) The trickiest category of the three. Lightly prune in early spring, cutting stems at different lengths.   BUDDELIA DAVIDII Prune hard in early spring at sign of new growth to two or three pairs of buds.   HYDRANGEA It's okay to leave on flower heads over winter, but cut them off in early spring and trim back stems to healthy buds. Rejuvenate old plants by lopping out large, old stems.   LAVATERA Wait until buds break after the last severe frost and then cut back hard, close to the ground.   LAVENDER Cut back too hard, too soon, and you lose the plant because buds don't break very freely from the old wood. Prune moderately in spring, harder once you see new growth.   PIERIS Prune for size and shape after flowering in spring.   WITCH HAZEL/ FORSYTHIA Prune selectively and moderately after flowering or as blooms start to fade.