What is the damage to our Japanese Maple leaves and how do you treat it?


Our newly planted Japanese Maples (Red Emperor) has signs of insect damage to its leaves. Do you know what could cause this and how best to treat it?


Jonathan Foster, Community Education Assistant

After bouncing the photos you sent along around among my colleagues to confirm first impressions, we are collectively of the opinion that the damage you are seeing is more likely to be environmental or mechanical than pest- or pathogen-related. The leaves show none of the tell tale signs we would expect from common Japanese maple problems, and the fact that they seem concentrated on the lower layers of the tree make us think it is either damage from a passing mower or leaf blower, a symptom of our droughty summer, or simply the sputtering out leaves from earlier in the season before you were able to transplant the tree to its current home. Japanese maples can be rather delicate and one colleague expressed admiration that yours looked so good after just being planted this season–please refer to her answer to a similar problem earlier in our series. It contains some excellent general care information, too.

I don’t think you’ll be dealing with this issue with a fresh flush of leaves next season.