GARDEN GURU

Q The branches of my crab apple are covered in woolly aphids. I have tried spraying them off with water, but within days they are back. Jenny Goodwin

A Woolly aphids are sapsucking insects that are protected by a white, fluffy coat, and they can form sizeable colonies. Blasting them off with water will help to reduce their numbers but I would suggest spraying them with an organic pesticide, such as Bug Clear Gun for Fruit & Veg. Several applications may be necessary to bring them under control.

Q When is the best time to trim a bottlebrush plant to restrict its expansion? Jan Ordowski

A These evergreen shrubs from Australia are grown for their cylindrical flower heads that drip from branches in spring and summer. It’s best to prune shoots lightly immediately after flowering, removing just below spent flowers.

Q My cherry tree is producing fruit but part of the trunk has peeling bark and oozing sap. What do you think is wrong with it? Linda Gill

A I’m afraid that your tree is infected by bacterial canker. If canker appears on branches, the branches can be pruned but this is not an option when it attacks the trunk. Continue to feed and water the tree, and it may produce more fruit next year. However, the damage looks quite severe so I’m afraid you will need to bite the bullet and remove the tree at some point.