Q. My mother’s mimosa tree was fine May 24. Something has attacked it. I have attached photos of before and after, with closeups of a couple of damaged areas. Please advise what we should do to help the tree. Mom is heartbroken.
A. I am not positive but it looks like Carpenter bee nesting damage. They usually bore holes into dead wood so I am guessing that the limb may have been under some stress and has been dead for awhile.
If these were from Carpenter bees then your Mom might have seen some large bumble bee like bees in the area. These are large bees that resemble bumble bees but fly faster and more zig zaggy and as brightly colored as bumble bees.
I am sorry there is not much you can do but remove the limb. With that much apparent damage I don’t think there is much you can do to save it. You can wait and see since they tunnel into dead wood but it might be severely weakened with that much damage. Mimosa is a fairly short lived tree and you were lucky to have it as long as you have.
This damage did not happen overnight. It has been going on for quite some time but plants have a way of handling damage quite well for long periods before they show signs they have been weakened. This tree is in the same boat. It has been damaged for awhile but never showed any signs until recently.