While winter pruning stimulates growth, summer pruning restricts it. This is because in summer the plants are in full leaf so you’ll be cutting off the leaves they need to produce energy and growth. It’s also crucial to prune plants that flower in late spring and early summer; prune at another time and you’ll remove next year’s flowers.
Plants to prune now:
• Wisteria. These climbers needs pruning in winter and summer to control their growth and to produce the best display of spring blooms. Tie in the main horizontal growth and upright shoots to their supports then shorten all side shoots back to 4-6 leaves from the main framework.
• Ornamental cherry trees. All plants in the prunus family can be attacked by silver leaf – a fungal disease that’s air-borne between September and June, so July and August are the safest times to prune them. Scour the plant for any dead, damaged and crossing branches, which may rub and cause wounds. Prune back to a main branch or an outward facing bud to encourage an open shape. Wait until next month to tackle fruiting plants such as peaches, cherries, plums and gages, pruning once you’ve finished harvesting.
• Blackcurrants. Modern cultivars such as ‘Ben Hope’ and ‘Ben Lomond’ produce fruit that ripens at the same time, which means you can combine harvesting and pruning. Blackcurrants fruit on the previous year’s growth, so prune out this year’s fruiting stems as close to the base as possible and harvest the currants at home. This year’s new stems will then have space to produce next year’s crop.
• Early-flowering shrubs. Phildelphus, weigela, kolkwitzia and deutzia can be trimmed after flowering to allow next year’s flowering wood to develop. Remove one-third of the oldest, thickest stems close to the ground and trim back any over-exuberant growth to just above a bud or pair of buds.