Question: There's a green fungus/mold type growth that sometimes appears on rocks in woody areas, growing on my trees. What is it? Is it a fungus, mold, lichen, or some type of disease. Do I need to worry about it? It seems to be on all trees in our area,but doesn't seem to be harmful. Rene Parenteau Johnston, RI
Answer: It's probably lichen that's growing on the trees and rocks. Although its living off of the trees, it causes no harm to the plants and should be enjoyed for the texture it adds! In short, don't worry about it.
Q&A Library Searching Tips
When singular and plural spellings differ, as in peony and peonies, try both.