Ask the RHS EXPERTS
Ashes to ashes
Q The ash trees near to where I live are diseased and dying – how can I protect my own mountain ash in my garden?
A The very destructive ash dieback fungal disease is slowly disfiguring and killing ash trees all over Britain. Although it attacks a wide range of ash tree species, the mountain ash and the very many related garden trees are different species being sorbus rather than fraxinus. Therefore, your mountain ash is safe.
Mountain ash and other sorbus are excellent garden trees and a good choice to replace ash trees in gardens that unfortunately become so damaged that they have to be felled.
BROKEN BROCCOLI
Q Some of my newly planted little broccoli plants have collapsed. Can you tell me why?
A Sudden collapse of newly planted cabbage family plants suggests the presence of cabbage root fly maggots. Look for grubs about half the size of a grain of rice on the roots and underground stems. Although, sadly, the plants cannot be saved, the cabbage root fly can be stopped by covering new plants with fleece or insect-proof mesh, or by placing a little, 8-10cm ‘collar’ of card-like material around the base of the plant at planting time. There will be at least one more generation of the fly in late summer. Happily, mature plants will tolerate damage, but younger ones will still need to be protected.
