Q: I have about a dozen fothergilla bushes. I just noticed that one of them has strange cone-like shapes growing out of the leaves! None of the others have anything like this. What in the world is this?

A: Fothergilla (witch elder) is a member of the same family as witch hazel (Hamamelis) and winter hazel (Corylopsis). All are afflicted by witch hazel gall aphid. This tiny insect causes the tissue of a fothergilla leaf to swell into a cone around her.

Fascinating Witchhazel Gall Research