Heathers are very hardy plants and relatively disease and problem free providing they are not allowed to dry out and are pruned and fed regularly. However, there are occasions when you may find yourself with a plant that looks worse for wear .... it could be due to the following:

Cats and dogs like heathers! If they 'spray', wash off immediately with clean water.

Look for Greenfly and Cuckoo Spit (aphid) attack in early summer. Cuckoo Spit is not a disease and although it looks harmful it has little detrimental effect on the plants - it can be wiped off with hand, treated with a jet of water or as per Greenfly, treated with an insecticide.

In periods of very wet muggy weather if the plant is badly affected with Grey Mould (Botrytis), treat it with a fungicide from your Garden Centre.