Is there treatment for my Red Japanese Maple that is showing signs of disease?


We have a Red Japanese maple tree that looks to be showing signs of disease. The bark is peeling and cracking and the crotch of the tree appears to have some rot. The leaves are not as full this year. There is no outward sign of insects that we can see. Last year, there were some ants on the tree but no signs of them this year. Do you know what could be causing this and is there any treatment?


Pamela Hargest, Horticulture Professional

Japanese Maple has very thin bark which makes it susceptible to winter injury and frost cracks. It appears this injury is old as the tree has already tried to heal this large wound. I suspect that between the frost cracking and the rotting crotch, your tree is suffering. These injuries certainly create the perfect environment for pests and diseases, but I don’t see any evidence of either.

I suggest letting your tree live as long as it can remain healthy, but it should be replaced once it really starts to decline. Be sure to protect your new tree from winter injury, here is more information: Protecting trees and shrubs in winter, University of Minnesota Extension