Control of Moss on Trees and Shrubs
Moss Control on Trees
In the Pacific Northwest, growth of mosses on trees and shrubs around your property is often lush. Mosses on trees are almost always accompanied by lichens. Fortunately, mosses and lichens are generally not harmful to trees and often look attractive. But, according to at least one source, wet mosses can be heavy and making trees susceptible to wind damage (Rost, 1998). On the other hand, tree care businesses say they get few requests for moss removal from trees and shrubs and that it is rarely necessary.
Consider the underlying causes of prolific moss growth. Generally mosses will be most developed on older landscape plantings under conditions of diffuse light. With more direct sunlight and air circulation around trees and shrubs, lichens are favored instead of mosses. In areas with substantial air pollution, neither lichens nor mosses are abundant.
If you want to change the mossiness
of your trees and shrubs, consider whether it is possible to change
the amount of direct sunlight. Increasing direct sunlight
may reduce moss growth but increased indirect light and diffuse
light may promote mosses. Please refer to other sections
of this web site, including Establishing
a Need for Control and Basic
Biology of Mosses for more information.
Physical Removal by Hand
The most common way to remove mosses from plants is by hand. This is labor intensive and will only be effective on shrubs. This is probably the best way to rid your shrubs of unwanted mosses. It is wise to do this during the winter when the plant is dormant so you do not damage active tree growth. You may do more damage to buds than the mosses will do if you are not careful.
You may be able to remove mosses from trees and shrubs by using a power washer to scour them away. This should be done in the winter when a plant is dormant so you do not damage it with the force of the water. Damage to buds even in the winter is an important consideration. This method is not suitable for delicate plants and may not prove too effective except on tree trunks and larger branches that do not have developing shoots.
Return to the main page of this section