Why do my blueberry plants have brown spots on their leaves?

Ami Martin, Cambridgeshire

AANNE SAYS This looks like a fungal leaf-spot disease, whose blemishes appear in late summer and autumn. Collect and bin (don’t compost) infected leaves to stop spores reaching the new foliage. Bushy evergreen blueberries like ‘Sunshine Blue’ tend to be more severely affected than deciduous varieties such as ‘Bluecrop’ and ‘Herbert’, whose less dense growth deters fungal diseases.

Blueberries are usually grown in large pots of ericaceous compost, as few gardens have soil that is acidic enough for them. Repot into larger containers if the roots are crowded and don’t let them dry out. Thin out stems by up to a quarter in February to improve air-flow and encourage new, productive growth, then feed with ericaceous fertiliser.