One of my favourite cottage garden plants is under threat — the aquilegia or granny’s bonnet. This spring I noticed that I had fewer aquilegias in the garden, and some that were growing had distorted leaves. I put it down to the late frosts we had had but then I discovered a far more sinister reason — ADM or Aquilegia Downy Mildew. This fungus has spread rapidly and has wiped out the wonderful National Collections of Aquilegia at Touchwood Nurseries, Killay, Swansea. ADM flourishes in cool damp conditions, just as potato blight does. Affected plants show irregular yellowish patches on the leaves and purple blotching on the stems. The leaves curl and become distorted and eventually the whole plant shrivels and dies. The spores of the mildew are on the underside of the leaf and can be difficult to spot in dry weather but they appear as white/purple in damp conditions. There is no known control and plants with ADM should be disposed of as quickly as possible — either by burning or burying. They should not be put in the compost bin. For further advice go to the very useful website of Touchwood Nurseries: www.touchwoodplants.co.uk My story has a happy ending as it was the frost that was causing the problem because other aquilegias in the garden have flowered as usual. However, I will be keeping a very watchful eye on them in the future.