Q: Bill, on the bark of my Crepe Myrtles, I noticed grayish growth. I can peel this growth off fairly easily. What is this growth and is it hurting my tree? A: It sounds like you have lichens. Lichens ...

Gardeners and homeowners often contact our Horticulture Hotline at Cornell Cooperative Extension in Oriskany when they notice a grayish blue-green crusty or mossy looking growth on trees, shrubs, ...

The chemical composition of lichens depends on the basis (substrate) on which they grow. Probably, in this way lichens adapt to adverse conditions - a high level of acidity (low pH) or the presence of ...

When I usually examine lichens, I am in a forest, peering at frilly growths on tree branches with my hand lens. Or on exposed rocks high in the Alps, or old gravestones, or the rocky seashore, in the ...