Why prune? The main purposes of pruning are: Early training: young trees and shrubs flower of fruit sooner, and develop into more attractive specimens, if they are pruned in ways that emphasise a well-spaced framework of branches. Early formative pruning aims to correct misshapen or excessive growth.

Maintaining health: controlling disease in an important part of keeping plants vigorous and attractive. Cutting out dead and diseased portions of branches, as well as removing rubbing branches, prevents further spread and disfigurement and, in case of trees, ensures that they are safe.

Keeping a balance: strongly growing plants can make a lot of leaf and stem growth at expense of flowers, while mature specimens may stop producing new growth and only flower erratically or t the branch tips. Routine annual pruning encourages a regular supply of young productive shoots while controlling more mature growth.

Improving quality: sometimes less is more; pruning can divert from heavy yields of small flowers and fruits into fewer, but higher quality, blooms. Similarly, some shrubs and trees with handsome foliage or bark are pruned to ensure plenty of young growth with enhanced colour or shape.

How pruning works: Several different hormones regulate plant activity. Those responsible for producing new growth tend to be concentrated in the top few buds of shoot tips where they encourage stems to lengthen while suppressing the growth of buds lower down. If you cut off these active areas of growth the plant redirects its energies elsewhere usually into the buds just below the pruning cut. In this way pruning is not just the removal of excess misplaced or unwanted growth but also the creative and predictable redirection of new growth.

When to prune: Early flowering deciduous shrubs Plants that flower during the first half of the growing season for example forsythia, philadelphus and weigela generally do so on stems that grow the previous year. Prune immediately after flowering to allow plenty of time for new growth in the second half of the growing season.

Late flowering deciduous shrubs Plants that flower later in the year do so on shoots developed earlier in the same year; for example buddleja davidii, caryopteris and perovskia. Prune during winter or wait until march or april as this helps to avoid frost damage to new growth.

Broad-leaved evergreens Most evergreens need little pruning exept to move dead material and maitain shape. Reguardless of whether they are flowering species such as skimmia, or foliage, such as spotted laurel, prune if necessary in april or may, since there new growth can easily be damaged by frost.

Conifers Apart from apart from removing dead material, you can trim ornamental specimens occasionally to encourage bushy growth and cut back the main shoot if it is growing to tall. Prune if necessary during autumn or early winter , to avoid the excessive gumming that occurs when the sap is rising. Do not prune in frosty weather. Trim coniferous hedges in late summer.

Pruning large branches Before cutting off a large tree branch, make sure you feel able to do the work safely. If in doubt, or the branch is more than 20cms (8ins) in diameter, consider hiring a qualifed tree sergeon, especially if the branch is well above the ground level. Make the final cut flush not with the trunk but with the branch collar, the swollen areas where branch and trunk join.

Raising the crown of an established tree The branches of a mature tree often bend under the weight of foliage, casting excessive shade and even becoming a hazard to anyone passing underneath. Raising the crown improves the situation by removing the lowest branches, this can involve taking off one or more sizable boughs. Where several large branches are involved , it is a good idea to spread the work over two or three years, re-assessing the shape of the tree each summer.

Thinning the crown Trees such as malus or sorbus develop a cluttered head of twiggy growth that may eventually cast unwanted shade and offer high resistance to wind, sometimes resulting in wind damage and disease. Removing some smaller branches and side shoots during winter can improve the air circulation. Carry out any further thinning the following midsummer, when you can assess how much reduction in shade you have already achieved.

The basic routine Never prune without a good reason and always cut off less rather than too much, because you can always remove more later. It is better not to prune at all rather than do the wrong kind of pruning in the wrong season or in unsuitable conditions, such as frost or drought.

Pruning young shrubs Early training and formative pruning deterime the future shape of a young plant and, if done correctly, will avoid pruning problems later on. .
Immediately after planting select the strongest three or four shoots as main branches and shorten them by half their length, cutting just above an outward-facing bud. Remove completely any weak and badly placed shoots. .
One year after Cut out weak and misplaced shoots, and any that cross the centre. Shorten the longest main branches to establish a shapely outline..
In the following years Start a regular routine of pruning the established shrub according to its type and flowering season.

Training standard trees Standard trees with a single stem 1.5m (5-6ft) high are rewarding tree forms in gardens because the clear trunk allows easy access all round, the other plants can be grown beneath without competition for light. There are two kind. . Central-leader standard retains a central main stem for the trees full height and is the shape favoured for forest and woodland trees, such as oak and beech. Cut out any competing main roots and prune side shoots off the trunk as the tree develops.

Branch-head standard is the preferred shape for most small ornamental trees like crab apples, cherries and rowans. Trained like this, the achieve a symmetrical arrangement of similar-sized main branches radiating from the top of the trunk. To create a branched-head standard tree: . For the first three or four years prune the basic rountine. . When for or five strong branches have developed abouve the required height of the main stem, prune back the central upright or 'leading' branch to a strong bud. . Afterwards thin out resulting side shoots to help develop an open symmetrical crown; remove strong vertical branches.