Plum tree problem
I have a three-year-old medley plum tree that is not looking healthy because it has spots on the barn. I don’t know what it is or what to do about it. I sure could use some help. It is three years old.
Certified GKH Gardening Expert
The "spot on the barn"? appears to be a wood decay fungal infection at the site of an old wound or pruning cut.. We can't see the entire tree so we assume that it is most likely a local infection at that spot on the tree trunk and not greatly affecting the overall health of the tree.
The only thing that you can do is to keep the tree as healthy as possible to help it resist advance of the infection and close the wound. Do that with good soil fertility and water management.