Maple tree health

Asked February 11, 2020, 7:09 PM EST

Hi! We have two Japanese maples which we inherited from previous owners. They are planted on a small, created, well-draining, berm and appear not to have been pruned in a while. I noticed what look like cankers on the trees and the one in the pics sent has not been leafing out well these past couple years. I am hoping for some suggestions re: what I can do to make the trees healthier and leafing out more. Should I prune out the areas with the cankers (would be a rather large bit off the one in the pics)? Thanks

Clackamas County Oregon

1 Response

I am a forester and not an ornamental tree specialist. But I do know that Japanese maples are prone to stem cankers and other problems, especially on older or neglected trees. Pruning out infected stems is generally recommended. See more information and recommendations for cultural treatments at

Sometimes, if trees are too far gone, you are better off to replace the tree with a young more vigorous specimen.