Pruning Small Trees
Ornamental garden trees require minimal maintenance, but sensible pruning can ensure the tree remains healthy and safe and grows in an attractive shape.
Although pruning does make trees slightly smaller than they would be without pruning, attempting to keep a big tree small by pruning is usually unsuccessful.
Deciduous trees (ones that lose their leaves in winter) are usually pruned in autumn and winter. In some cases, for example with magnolias and walnuts, pruning is best done in late summer, as healing is quicker.
Trees such as Prunus sp, which are prone to silver leaf disease are best pruned from October to February when the disease spores are not on the wind, and the tree sap is rising rather than falling (which pushes out infection rather than drawing it in).
Some trees can bleed sap if pruned in late winter and early spring. Although seldom fatal, this is unsightly and can weaken the tree. Birches and walnuts often bleed if pruned at the wrong time.
Evergreens seldom need pruning, although dead and diseased branches can be removed in late summer.
Established hedges require trimming to keep them dense and compact. Formal hedges require more frequent trimming than informal hedges.
New hedges require formative pruning for their first couple of years after planting. Formative pruning is usually carried out in winter or spring.
After this, maintenance trimming is carried out, usually once a year for informal hedges and twice a year for formal hedges. Some formal hedges may need three cuts a year. Maintenance trimming is generally carried out between spring and summer.