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Young hackberry tree nodules on leaves #944950

Asked September 13, 2026, 1:34 PM EDT

Hello, I have a new boulevard tree this year. Recently, I have noticed these nodules that are attached to the leaves. They are hard to the touch. Are these harmful to the health of the tree? I have noticed them on other hackberries as well. Thank you.

Ramsey County Minnesota

Expert Response

Thank you for writing. 
These are hackberry galls
https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/hackberry/leavesgrowths.html

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

https://mdc.mo.gov/discover-nature/field-guide/hackberry-psyllids-hackberry-nipple-gall-makers

You may safely ignore them.
Steve Miles, Master Gardener, Hennepin County, (I am a volunteer human being: not a bot, not AI). I'm an avid gardener but not a degreed or certified horticulturist or arborist. I will do much better if you also send a photograph. I like follow-up questions.  The University' garden soil tests are excellent.  https://soiltest.cfans.umn.edu/testing-services/lawn-garden This is how to find a tree expert.  https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional  A Directory of ISA certified arborists is at https://certificates.directory.isa-arbor.com/  The Minnesota Landscape Arboretum is a wonderful place to see and learn about plants that grow in Minnesota. https://mngardens.horticulture.umn.edu/minnesota-landscape-arboretum  Ask a Master Gardener is a public service of the University of MInnesota's Extension Division.  Please donate if we make you happy.  https://give.umn.edu/gardener Replied September 13, 2026, 2:28 PM EDT

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