Chances are these are leaf galls.
Leaf galls are a plant’s way of healing itself, though they can be a jarring sight.
However, by the time you see those bumps, the insect has long since moved on.
The Spruce / K. Dave
Below, we’ll discuss leaf galls, what they are, and how to identify and treat them.
What Are Leaf Galls?
The gall itself is the plants response to the irritation.
The Spruce / K. Dave
Before they do, they can do a lot of cosmetic damage to many plants and in particular trees.
Galls can also form on stems and flowers.
However, leaf galls seem to be the most prominent and get the most notice.
The Spruce / K. Dave
Mature leaves are rarely affected.
However many common trees are susceptible to leaf galls, especially when first leafing out in the spring.
Damage will be more considerable following a mild winter since more insects have survived and are hungry.
That is true of any insect problem in your yard or garden.
Contact your local extension office for specific guidelines and recommendations in your area.
Galls on Trees.Missouri Botanical Garden
Plant Galls.The Morton Arboretum
