Small cotton like balls dropping from oak tree

Asked October 12, 2020, 1:21 PM EDT

We have been in our house 23 years this month. A mature oak tree that is on property line is dropping small, pinky finger tip size, cotton like balls. They have hard centers. What are they? Puppies keep trying to eat them. Cut one open, seems to have hard red shell, white inside.

Kent County Michigan

1 Response

Your white cottony balls are galls. Galls are commonly found on many types of plants, especially oak trees, and usually are not a significant problem. Galls can be formed in several ways, but there is usually a specific insect, mite or plant disease organism involved. Your particular gall is likely a wool sower gall.


Please see the link below for more information on plant galls.


I do not know if ingesting the galls would be harmful to your puppies, but to be safe, I'd try to keep them away from the puppers. The best thing for you to do now is to rake up and destroy the galls and dispose of them in the trash. This will reduce the number of mature insects that are present next year.