I have two wisteria bushes next to each other. One leafs out earlier than the other and looses it's leaves sooner than the other. It's been a month since the leaves haven fallen off one bush and the other still has a large portion of yellow/green leaves. What seems to be the problem and if so what can I do?
This could be a difference in microclimates between the location of the two wisterias. One might be exposed to slightly more sun or warmth earlier in the spring, causing it to leaf out earlier. The other wisteria would then be behind its schedule for the etire season. I don't think this would be harmful, though. Here are some other reasons the other wisteria may produce its leaves late: