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Growth on leaves of a tree #869175

Asked May 19, 2024, 10:06 PM EDT

The tree in our back yard (Lakeville MN) has strange red "spikes" on many of the leaves. What is it and do I need to do anything about it?

Dakota County Minnesota

Expert Response

Thank you for writing.
This is Linden Leaf gall. An insect bites the tree and puts a bacteria or virus into the leaf that causes these bumps. They are common and rarely anything to worry about.
https://horticultureforhomegardeners.ca/2021/06/21/spindle-galls-unusual-growths-on-linden-leaves-caused-by-eriophyid-mites/

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 May 19, 2024, 10:29 PM EDT

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