The bumps are called galls. They are caused by insects - the bump itself is basically scar tissue. The galls are typically cosmetic in nature, they aren't hurting your tree. I know they can be unsightly, but they're pretty normal occurance.

Here is a little more information on galls you'll find on Hackberries and general information:

Hackberry galls: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/hackberry/leavesgrowths.html

Insect and Mite galls: https://extension.umn.edu/yard-and-garden-insects/insect-and-mite-galls

Received From: Pamela <stree013>

Thanks for the information.  Glad to hear that galls won’t damage the trees.
Pam
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On Sep 2, 2021, at 8:24 AM, Ask Extension <askextension> wrote:

Dear Pamela, here's the response to your question:


The bumps are called galls. They are caused by insects - the bump itself is basically scar tissue. The galls are typically cosmetic in nature, they aren't hurting your tree. I know they can be unsightly, but they're pretty normal occurance.

Here is a little more information on galls you'll find on Hackberries and general information:

Hackberry galls: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/hackberry/leavesgrowths.html

Insect and Mite galls: https://extension.umn.edu/yard-and-garden-insects/insect-and-mite-galls



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