Oriental Maple tree

Asked June 26, 2019, 8:13 AM EDT

There is a mature oriental maple in my back yard. I've been caring for it for four years. The first year it was beautiful, no problem. The last three years the leaves dry up and turn brown; about 50% of the tree. It starts out very healthy, however about this time each year the leaves turn brown. The only thing different after the first year is we planted hostas under the tree. The ground is covered with large ones. I could take pictures of the leaves, if that would help. I hate to lose this beautiful tree. Thanks

Ingham County Michigan brown leaves oriental maple

1 Response

Japanese maples are susceptible to several fungal diseases. One (Botryosphaeria canker) infects branches that have been weakened by freezing, harsh winter conditions or other environmental stresses. The result is cankers on the branches and dieback of the infected branches.
https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/450/450-726/450-726.pdf
Look for sunken or discolored areas on the bark of branches with the leaves that are turning brown. The cankers can enlarge slowly, resulting in trees that decline over time. Verticillium wilt is a fungus that lives in the soil, and makes its way into the water conducting tissues and plugs them up. You can send samples in to the MSU diagnostic clinic on campus
( https://pestid.msu.edu/submit-samples/ ) if you suspect that one of these diseases is the cause. Here is some information about verticillium wilt:http://learningstore.uwex.edu/assets/pdfs/A2537.pdf