Help…My japanese maple has yellow patches and white spots all over its trunk. It was planted about 3 years old and is in full sun in my backyard in Toronto.
What is it and what do i do to fix it?
After considerable searching on various Master Gardener websites and in several tree books in my own library, I can find no indication that these spots present a problem. It is most likely lichen, which will not harm the tree. If it bothers you, perhaps you could hose it off, but it’s not necessary to do so to save your tree. If you would like a second opinion, you could take your photo to a reputable nursery and show it to an experienced plantsperson or contact an arborist. To prevent disease, be sure that you use clean tools for pruning and cleaning up around your tree.