Cherry Tree Root Burl
I have a 40 year old cherry tree in my yard. About 15 years ago it started to produce burls at the ground surface of my lawn 10 ft from the main trunk. In the last 3 years they have started increasing in height above the lawn surface so now they are 4-5 inches above the soil. Can I cut these burls off at ground level without killing the tree?
Ingham County Michigan
From your description, it appears that your cherry tree has crown gall which causes abnormal growths on its trunk or roots. The growth is caused by bacterium called Agrobacterium tumefaciens which lives in the soil and enters the tree’s roots through wounds that the tree suffered during planting or insect wounds and frost heaving. There is no treatment. In an orchard, the tree would be removed and destroyed.
The University of Minnesota Extension states in a bulletin, https://extension.umn.edu/plant-diseases/crown-gall: “Mature trees, such as yours, may tolerate many galls without serious effect but it may be more susceptible to drought stress, winter injury and secondary diseases that may enter the plant through cracks in the gall”. If you cut off the gall, you would provide such openings and cause the tree more stress.
The tree may last more years with little effect. If you decide to replace it with another cherry tree, the roots of the new tree should be treated before planting to prevent an attack by the bacterium. Another bulletin from MSU Extension https://www.canr.msu.edu/news/crown_gall_is_a_disease_of_both_woody_ornamentals_and_herbaceous_perennials provides more information on treating new trees.
You can also consult an arborist about your tree. Go to www.treesaregood.org the website of the International Society of Arboriculture to find a certified arborist near you.
Thanks for your question and good luck with your tree.