Expert Advice for Garden Pruning
Sensible garden pruning benefits both plant and gardener, but injudicious pruning can be disastrous. If a forsythia hedge is pruned at the wrong time, for instance, the result the following spring can be plenty of leaves but no flowers.
Many frees and shrubs will grow happily for years without pruning, but in many cases garden pruning leads to more prolific flowering and a better shape. Shaping is seen at its best in topiary, which is quite feasible for.
Garden pruning also provides an opportunity to remove dead or diseased wood, so it also contributes to the general health of garden plants.
Good gardening tools obviously help, and they should be sharp.
When to Prune
Dead wood should be removed as soon as it is noticed, at any time of the year; the same applies to diseased shoots. For general shaping and to improve cropping, however, the time should be chosen carefully.
Deciduous shrubs or trees are usually pruned in the dormant season, particularly if a large amount of wood is to be removed. This reduces the risk of infection and does not subject the plants to a severe check to growth. But there are exceptions; silver leaf disease, which affects plums and other Prunus species, is less likely to become established if pruning is done when the plant is in full growth, preferably before mid-July.
Where flower and fruit buds are to be encouraged in preference to rampant growth, summer garden pruning is also desirable. This applies particularly to fruit trees of restricted form, such as cordons or espaliers.
Shrubs that flower on wood produced in the previous season are usually cut back after flowering; this allows time for replacement shoots to grow and mature for next season’s flowers.
Shrubs that produce flowers on new growth are best pruned early in the year, to encourage a flush of vigorous shoots. The butterfly bush (davidii) is an example of a shrub that responds to this treatment; to delay pruning may mean all the potential flowering shoots for the current year are removed.
As very early hard cutting back may encourage growth during periods of frost, it is wise to head back the shoots by half in the autumn or winter, and then complete the job when the first sign of growth appears in March. In this way any early shoots damaged by cold can be replaced by others formed lower down the stems after the second pruning.
How to Prune
Always start by cutting out dead or diseased wood, cutting back into sound areas of the branch.
Where it is necessary to remove an entire heavy branch, it is best to make an undercut before working down from the upper part of the bough, as this will prevent the bark being torn. The weight of the branch sometimes causes the saw to bind when undercutting, in which case first cut off the branch about 30cm (1ft) from the main branch or trunk.
Once the branch has been removed, clean up any rough edges on the wound, using a sharp knife, then apply a bitumen wound dressing paint, making sure the whole area is thoroughly covered.
Even on smaller shoots or twigs, it is unwise to leave short snags that may die back eventually. Using secateurs, cutjust above a suitably-placed bud, ideally sloping down away from the bud slightly. If using a garden pruning knife, make the cut upwards towards the tip of the bud.
If you are trying to encourage the plant to fill in the centre, cut back to an inward-facing bud, but if the plant is overcrowded or a weeping habit is required, choose an outward-facing bud.
Special Cases for Garden Pruning
Roses often generate controversy when it comes to garden pruning, and this aspect can be found under “Caring for Roses“.
Fruit trees are often complex in pruning requirements, particularly if trained as cordons, espaliers or fans. For that reason pruning is discussed under the relevant fruit.
Clematis often cause difficulties -mainly because one has to decide on the type of clematis being dealt with, and there are different methods of pruning. There are three main groups:
- The small-flowered species normally only need light pruning, sufficient to prevent shoots becoming overcrowded and to maintain a good shape. Dead or unproductive stems can be removed at any time, although late-flowering species can be cut back hard in spring to encourage a new flush of vigorous growth if the plant has become totally overgrown and tangled. Early-flowering species, such as C. montana, are best pruned just after flowering.
- Large-flowered types that flower on previous year’s shoots, and normally-lower in May and June, should be back lightly after flowering. Tangled specimens can be cut back hard February if you are prepared to lose first crop of flowers.
- Large-flowered types that flower on wood, such as the Jackmanii range (these normally flower later), can have stems cut back to within 30-90cm (1-3ft) off the ground; this promotes plenty of flowering shoots at eye level. If is not done, the plants continue to row upwards and soon reach tall proportions with large areas of bare stems yards the base. Garden pruning for this type is best done in February or March.