Pruning is done for a variety of reasons - to promote bigger harvests, get newly-planted trees and shrubs off to a good start, thin crowded stems, train cordons, fans and espaliers, encourage flowering, shape plants, remove diseased wood and promote vigour.
Discover some key plants to prune in winter.
With a few exceptions, all of these jobs can be done in winter, when bare stems make the job of shaping shrubs and spotting diseased growth much easier.
For details on how to prune, see our practical project on how to winter-prune trees and shrubs.
We explain why you need to prune in winter.
When shrubs or trees are newly planted it's important to encourage formation of a good root system. New shrubs should be cut back to a few buds so that the plant can devote its energy to putting down roots in the first season. New fruit bushes should be thinned to just three branches. Newly planted trees should be pruned to reduce the 'sail' effect of top growth, preventing wind rock.
On plants where growth is constantly renewed from ground level, the weak, spindly shoots should be removed, as well as some of the oldest stems. With plants such as hazel, the oldest shoots should be thinned out to prevent overcrowding. Simply remove large branches from older shrubs.
Training fruit trees
Having established the main framework by tying in major branches to the support, side shoots should be reduced to two or three buds to make short spurs. Much of the work should be done in August and September, but it can be continued into winter. Discover three ways to train a fruit tree.
Promoting summer blooms
Shrubs that flower after midsummer can produce flowers on new growth. They can be manipulated to ensure the flowers grow at the desired height. Branches can either be cut back hard or thinned into a nice shape. Large shrubs such as buddleia should be pruned hard to stop growth getting out of control, while smaller shrubs such as hardy fuchsias should be cut back to promote larger blooms.
Winter is the ideal time to assess and modify the shape and structure of trees and shrubs. It's difficult to evaluate what's happening when they're covered in leaves. With crab apples, lop-sided shoots should be removed, while competing leading shoots should be taken out of trees such as rowan. Shrubs such as Viburnum opulus should be pruned into a vase shape.
Diseased branches should be pruned out to maintain the health of many trees and shrubs, removing any dead, dying or diseased branches. Apples and pears should be pruned to remove branches infected with canker, magnolias should have dead stems removed to control verticillium wilt. Don't prune plums and related species during winter - it can lead to the spread of silver-leaf disease.
Pruning in this way removes weaker stems to promote stronger growth of existing stems, or removes existing stems altogether to encourage fresh, new growth. Plants grown for their colourful winter stems, such as dogwood, Cornus alba, and white willow, Salix alba, should be cut back hard or 'stooled' in late winter or early spring, to around 15cm above ground level. Other shrubs should have the thinnest, spindly growth removed.