Q Can I reduce a 1m-tall box hedge by a third?

Bruce Wass, East Sussex

A BOB SAYS If your hedge is weak but not obviously diseased (several pests and diseases are currently seriously injuring box), then feed and water it generously for one growing season to revive its vigour. Then you can cut it back by a third in late April to mid-May. Continue feeding and watering after pruning.

Healthy box (Buxus sempervirens) can be cut back hard in late spring