Thorny growth on tree leaves.

Asked May 6, 2019, 12:21 PM EDT

What is causing these horn-like growths on the leaves of my backyard tree? They’re stiff but not sharp, hollow inside, paired top and bottom of the leaf. Appearing for the first time this year, so far only on lower limbs. Should I remove the branches? Cut down the tree? Not worry?

Anne Arundel County Maryland leaf galls trees pest insects and mites

1 Response

The growths on the leaf are a type of hickory leaf gall. These are formed by the tree in response to an insect. The overall health of the tree is usually not affected. There are no treatment recommendations. Galls are fairly common in some trees at this time of year. This doesn't look severe and it's nothing to worry about -- definitely don't cut down the tree!

Here is more information about leaf galls. https://extension.umd.edu/hgic/topics/shade-tree-galls

Christa