Oak – Wooly Leaf Gall
Q: I found this leaf with the fuzzy elongated growth stuck to it in my yard. Can you tell me what the growth is?
A: It’s a wooly oak leaf gall. It’s caused by an insect that lays eggs on the leaf veins in spring. The leaf grows over the eggs in this characteristic shape.
There are lots of other oak galls: sower gall, apple gall and cherry gall, to name a few.
There’s nothing to be concerned about.