Ask a Consulting Arborist Q&A: Leaf, Seed, and Flower Concerns

Q: Chinese elm has begun developing blisters on its leaves. Is this harmful to the tree?

Wednesday, December 30, 2015   (0 Comments)
Posted by: Shannon Sperati

Q: The tree in my back yard has begun developing blisters on its' leaves. Once blistered the leaves turn yellow and fall off earlier than they should. I've been told the tree is a Chinese Elm. I'm unsure what to to do. Should I have the entire tree removed immediately? Any feedback you can send would be very helpful.

A: Typically, blisters are the leaf's response to the laying of eggs by some passing insect. By the time you notice the blisters, the culprit is long gone. The good news is that the damage is superficial and won't have long-term deleterious effects on your tree. Yellowing and leaf drop are the tree's way of shutting down the less healthy leaves and diverting energy to more productive ones. No treatment necessary, and you hope the tree rebounds next season. Secondly, if your tree has a true "blister" condition, a disease caused by fungi, the tree is potentially more at risk, but the recommendation remains the same, to 'do nothing' as you wait to see how it fares. Check out the following link to Virginia Tech science on the matter:

Overall, you should not have need for undue concern or for treatment of any kind. Good luck with your elm.


Responder: David Jahn, RCA #425, Des Moines, IA