Our Japanese Lilac has a bad problem

Asked July 25, 2016, 7:30 PM EDT

Hi, Our 20+ year old Japanese Lilac tree has developed a bad problem on a couple of the branches. I don't remember seeing it last year, but I can't imagine that it got this bad in one season, so I probably just didn't notice it. Can you please take a look at the attached photos and give us any recommendations on how we should proceed with treatment. We'd really hate to have to cut it down as the spring fragrance is beautiful. We're members at the Arboretum but thought we'd ask here first. Thanks, Mike & Debbie Given Chanhassen

Carver County Minnesota

1 Response

It appears this issue began with damage to this branch either in the form of a frost crack or loss of an adjoining branch that broke off in a storm. The wound is severe and the tree was unable to heal properly. This created a wound / exposed wood that opened the tree to various potential pests. Insects may be tunneling under the wood and exiting via the holes or, more likely, woodpeckers and other birds that feed on insects in trees are making these holes. If the damage is isolated to just this branch, you could prune off the branch. If damage is noticeable on other parts of the tree and/or if you notice dieback in the canopy, then you may need to remove the tree entirely. A certified arborist can help assess the rest of the tree and determine the best next steps if you are not sure.