Smoke Bush (tree) Looks Dead By Mid-summer Every Year

Question

I have three very large purple smoke bushes, possibly 40+ years old, in southern and western light; they were here when I moved in. I live in southern Ohio (zone 6). They always come up beautifully in May and stay that way until mid-June. When it gets really hot (high 80s – 90s), and we get less rain, the leaves start to die. Usually this happens in early/mid July. This year the bushes have lasted a little longer and look kind of mediocre instead of fully in the throes of dropping dead. The heat was not as bad and the rain lasted a little longer into the summer than usual and this makes me think that the heat is the problem. The lawn service prunes them, once in June and once in August. I do not water them. I’m wondering – should I? Are they croaking because of lack of water or because the heat is too challenging (or both?)? I’ve read that smoke bush is drought tolerant. I don’t think they have vert wilt because then they wouldn’t be able to rise back up every year – yes?

Answer 1

Are you watering enough? They are unfazed by my 100+ degree temps from July through September but they can suffer from verticillium wilt, which will cause sudden dying back of the branches. If the plant does become infected with this soil-borne fungus, it must be replaced. I never prune mine.

https://www.gardeningknowhow.com/ornamental/trees/smoke-tree/smoke-tree-verticillium-wilt.htm