Thundercloud Purple Plum Leaf Disease
Purple Plum trees across the state have suffered from the unusually warm winter when they did not fully harden off, then we had a blast of very cold temperatures during February. Many of these trees are under stress, have lost entire branches or died out right. The buds that did live may produce smaller leaves, and many flower buds dies.
Your leaves appear sun scalded. They do not look like the spots are from insect damage or disease.
Thank you Carol. Can I expect any improvement this year or will I need to wait unit next year? About 1/3 of the leaves are affected.
Water well during dry times to lessen stress. Prune off any suckers from the base so the tree does not waste energy on unnecessary growth. Other than that, I think it is a wait and see how it does. On rare occasions, trees refoliate the same year, but should recover by next year if we have a normal winter.