Our wisteria, which is 20+ years old, is showing some very small, dry looking leaves. I did see the info on gall but don't see any signs of that. I appreciate your help.
I would check for crown or root galls. Here is some information on them that may be helpful: https://www.gardeningknowhow.com/plant-problems/disease/how-to-fix-crown-gall.htm
If that doesn't turn up anything, it may have a fungus. Treat the plant with a fungicide. I like neem oil, as it will also deal with any pest issues the plant has and it is safe for people and pets. Here is more information on it: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm