Gardeners are being urged to prune stone-fruit trees such as plums, cherries and apricots during the summer months to prevent fungal and bacterial diseases. Unlike many other fruit trees, which are pruned in winter, established Prunus family trees should be cut now to reduce the risk of silver leaf disease and bacterial canker.
Silver leaf disease is transmitted by spores active in autumn and winter, infecting trees through open wounds and causing leaves to turn silver and branches to die back. Pruning in summer allows wounds to heal before the colder months, minimising infection risk. Bacterial canker can also enter susceptible trees during winter, making summer pruning a prudent measure.
When pruning a plum tree, start by removing dead, damaged or diseased branches—the three Ds. Then, cut any crossing branches to prevent abrasions that can let disease in. The next step is to reduce growth by about a third while maintaining an open, goblet shape for good air flow and vigour. Shorten branches, remove vertical watershoots, address congestion at the centre, and eliminate suckers at the base.
Use clean, sterilised equipment and make sloped cuts above outward-facing buds to direct new growth. Step back regularly to ensure the tree remains balanced, as cuts now determine future shape. Judicious pruning not only boosts fruit production but also ensures long-term tree health. For neglected trees, a patient, gradual approach over several years can restore them to fruit-bearing glory.
