WSU Extension

Hortsense

Common Cultural : Mosses and lichens
(revision date: 4/30/2013)


Biology
Mosses and lichens are primitive plants often found growing on the bark of older trees and shrubs. They are typically grayish, greenish, or orange in color and may be flat or branched. Mosses and lichens are not parasitic and will not harm the trees. They are often associated with shaded or declining trees, but do not cause decline. Regular pruning usually limits development of mosses and lichens.
Management Options

Non-Chemical Management
  • Plant in sunny locations. Prune to allow more light into the canopy.
  • Provide proper plant culture. Vigorous trees are not at any risk from moss and lichen development.
  • Remove heavy buildups of mosses and lichens by hand, when practical.
Select non-chemical management options as your first choice!

Chemical Management

Fungicides are not usually recommended.

Images
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Caption: Lichens on rhododendron branches
Photo by: C.R. Foss
Caption: Lichens on rhododendron branches
Photo by: C.R. Foss
Caption: Lichens on walnut
Photo by: J.W. Pscheidt