Constant pruning of many trees and shrubs is not a necessity, but rather it’s done for aesthetic reasons to improve flowering, stem colour and foliage and, if necessary, to control size. Here are three plants that benefit from late-summer or early-autumn pruning.
Maples (Acer spp. and cvs.) Because these trees bleed sap if pruned in late winter and spring, maples should be pruned in late summer or early autumn when the sap is not rising.
Birch (Betula spp.) These trees generally require little pruning. With the many smaller shrub forms available, selecting a size and shape that’s appropriate for your space reduces the need for pruning. However, if pruning is required, do it in late summer or autumn to prevent wounds from bleeding badly.
Wisteria (Wisteria spp. and cvs.) Wisteria is another heavy bleeder that should not be pruned in spring. To promote flowering and contain its size, do the first main pruning in early to mid-summer. Cut back the lateral, or trailing, growths to approximately 15 centimetres. Then, in early or mid-winter, shorten the growths even further, cutting back to two buds. An alternative to this method is to cut back excess trailing growth throughout the summer over a period of weeks.
Here are Vineland Nurseries’ Jim Lounsberythree three top tips for fall pruning.
- Prune no more than 10 per cent of the overall size of the shrub or vine.
- After about the middle of October, wait to prune until plants are fully dormant.
- Prune macrophylla-type hydrangeas down to the first fat bud, never right down to the ground. If you prefer to leave the dried flower heads for winter interest, wait until spring to prune to the strong bud.
Photo: Janet Davis