Walnut Tree in August: monthly care

Walnut trees require very little pruning and should only be pruned in late summer—specifically August or September—when the sap flow has slowed. Pruning in winter or early spring causes severe "bleeding" of sap from cut surfaces, which weakens the tree and invites fungal infection. Never prune walnuts between November and July. In the first few years, focus on developing a clear central leader and a well-spaced framework of branches. Remove any shoots growing from the base of the trunk and any branches that cross or rub against each other. Aim for an open, balanced crown with main branches spaced evenly around the trunk. Once the tree is established—usually after four or five years—pruning becomes minimal. Mature walnuts need only light maintenance pruning. In August or September, remove any dead, diseased, or damaged wood, cutting back to healthy tissue just above a bud or side branch. Take out any vigorous upright shoots (water sprouts) growing from main branches, as these rarely fruit well and clutter the canopy. If two branches are competing or crowding each other, remove the weaker or more poorly positioned one. Use sharp bypass secateurs for stems up to 2 cm thick and a pruning saw for anything larger. Make clean cuts at a slight angle to shed water. Avoid removing more than 10–15 per cent of the canopy in any one year. If a large branch must come out, consider hiring a qualified tree surgeon—walnuts are big trees and heavy limbs need safe handling. Resist the temptation to over-prune; walnuts fruit on wood that is two years old or more, so excessive cutting reduces your harvest.