What to cut back in summer
Don’t neglect these essential pruning jobs, says Ruth
CONVENTIONAL wisdom says we prune trees and shrubs in autumn and winter when they are dormant, but there are several varieties that ought to have a haircut in summer.
These largely fall into two categories; those that are susceptible to silver leaf disease; and shrubs that flower in early summer and create each year’s blooms on strong young growth produced the previous year and early the next.
A third group are evergreen shrubs that are less hardy can be damaged by cold if trimmed in winter.
This week I have been busy pruning our recently flowered philadelphus and weigela, giving a straggly ornamental flowering cherry a muchneeded tidy up, and pruning our plum and greengage trees.
I also checked over a variegated euonymus and found a small case of reversion, where the green-and-white leaves had been replaced by solid green foliage. This needs to be pruned out otherwise it will eventually take over the whole plant. Silver leaf disease is a condition caused by the fungus Chondrostereum
purpureum, which has spores that are active in autumn and winter.
It affects a wide range of trees, including cherries, plums, apricots, rhododendrons and laburnums.
Affected leaves develop a silvery sheen and their branches die off. When cut through, the branches may be darkly stained and older dead wood may develop bracket fungi with a white woolly surface.
By pruning vulnerable varieties in summer you remove the risk of infection, especially as pruning cuts heal faster at this time of year. Where any silver leaf develops you should remove and dispose of the affected branch as soon as possible and thoroughly disinfect tools afterwards.
When summer pruning fruit trees aim to create an attractive open shape that allows good ventilation and lets lots of sunlight on to the ripening fruits. Cut back over-long ‘whippy’ branches that could be in danger of snapping and support any that are heavily laden with fruit, so they don’t break.