What They Are
These fascinating plants are actually the result of algae and fungi working together to survive. Many different types of lichens can be seen around our city trees, generally on the trunk and branches. It’s not uncommon to see several varieties of lichens on one host tree, either in small clusters or flaky patches. Lichens are non-parasitic and exist without harming the host tree; therefore, treatment is not necessary.
If your tree seems to have too much lichen growing on it, chances are that the host tree has poor health. The heaviest lichen colonies generally take place on young trees that were planted poorly, were over-pruned, or have poor heath.