Q: Have you ever seen this? My oak tree has been producing little red berries or acorns! I know what an acorn looks like and these are not acorns. But they were growing from the tree in several locations on the tree.
I do have wild cherry trees growing in my backyard also. Could this be some kind of cross breed of oak and cherry?
A: Oaks seem to have more gall-making insects afflicting them than any other tree. There’s bullet gall, jumping gall, gouty gall, sower gall and hedgehog gall. There’s oak marble gall, horned oak gall, noxious oak gall and oak apple.
All galls are caused by an insect of some sort wounding some part of a plant in order to lay eggs. The insect injects hormones at the wound which cause the tissue around that spot to grow abnormally. The abnormal growth often serves as home for the insect’s eggs and young.
Since the insect depends on the continued growth of the plant in order to have a place to lay eggs in the future, galls rarely harm the host.
For that reason, the only control I recommend is clipping off the gall if it bothers you.
If you really want an education on plant galls, refer to the exhaustive “Key to American Insect Galls”
Your’s may be an oak cherry gall but I am by no means positive.