Gardeners who own cherry, apricot, peach, or plum trees are being warned to take immediate action this July to protect their trees from a potentially devastating disease known as silver leaf disease, according to Jacksons Nurseries.
Silver Leaf Disease: A Serious Threat to Stone Fruit Trees
Silver leaf disease, caused by the fungus Chondrostereum purpureum, is an airborne bacterium that enters trees through pruning wounds and weakens them over time. The garden centre's manager, Hayden Salt, described it as a 'serious threat' to a wide range of fruiting trees, noting that despite its pretty name, the disease can be very bad news.
The disease gets its name from the silvery sheen it gives to leaves, which is a sign that the affected branches are struggling to photosynthesise properly. Over time, this can lead to branch dieback and even the death of the tree.
Why July Pruning Is Crucial
Many gardeners believe winter is the best time for pruning all fruit trees, but Hayden Salt warns that for stone fruits, this is a mistake. Pruning stone fruit trees during colder months, when sap is retreating into the roots, creates a vacuum that can draw fungal spores directly into the exposed wound, giving the pathogen a perfect opportunity to take hold.
In contrast, pruning in July and early August aligns with the tree's natural flow of rising sap, which helps flush out and repel fungal spores rather than allowing them in. This means gardeners are making use of the tree's own defences, giving wounds the best chance to heal cleanly and without infection.
How to Identify and Prevent Silver Leaf Disease
Gardeners should look for leaves that have a silvery or metallic sheen, which is the most obvious symptom. Other signs include branch dieback and the appearance of fungal fruiting bodies on dead wood. To prevent the disease, prune stone fruit trees only in summer, ideally in July or early August, when sap flow is strongest. Avoid pruning in wet weather, as spores are more likely to be present. Always use clean, sharp tools to make clean cuts, and remove any infected branches immediately, cutting well below the affected area.
Jacksons Nurseries also advises gardeners to dispose of infected wood properly, either by burning or removing it from the garden, to prevent the spread of spores.
