A lot of fruit trees and trees that have been around about 10 years or more might get lichen on the tree. It’s this crusty, green moss the tends to grow on the bark of trees at least 5 to 10 years old or older.
Lichen is a unique organism because it’s actually a symbiotic relationship between fungus and algae. The fungus grows on the tree and can collect moisture which the algae need. The algae, in return, create food from the energy which feeds the fungus.
This non-parasitic organism collects water and minerals from the air and in turn, contributes photosynthates and other nutrients back to the tree and the air. You might begin to wonder if it’s harming the tree, but don’t panic, it’s actually not. In reality, most of these lichens grow because of the good air quality and they tend to grow more abundantly on trees exposed to a lot of sunlight. If a tree is declining or has a thin canopy, more sunlight will reach the trunk and make it an attractive area for this lichen growth.
While it’s probably not hurting the tree, it could be a sign that there might be something wrong with the tree. If you have a tree or shrub with excessive lichen, evaluate if there are any other problems with the tree such as stress, disease, or pest problems. Compacted soil, nutrient issues, and root problems could also be a factor so while the lichen doesn’t harm the tree specifically, it could be an indicator of additional problems.
But what if you want to get rid of it?
While it’s not a problem for of the tree it can be not so pretty to look at. You can gently scrub the bark of the tree with a soapy solution since it’s barely hanging on to the trunk. But if you scrub too hard it could damage the bark, opening the tree up to disease or insects. You can also spray the tree with a copper sulfate. This will kill the fungus side of the organism. A lime solution may also work but be cautious to not get it on the roots or leaves.
Probably the best solution is to change the environment. Thin out the branches to allow more air flow may help and make sure your sprinklers are not “watering” the lichen on a regular basis. Have more questions? Give us a call anytime!
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