Water Oak – Welts and Blisters

Q: My water oak has welts and blisters on the front and back of leaves and new foliage that appears shriveled. What is it?

A: Your tree has oak leaf blister. Most of the infected leaves will fall from the tree. This disease is favored by cool, wet springs; in dry years it isn’t a problem. Despite the leaf drop, trees are rarely permanently affected. Get out your leaf rake and clean up as needed!