When properly applied, mulch offers many benefits, such as conserving soil moisture, regulating soil temperature, suppressing weeds, and even enriching the soil when an organic mulch decays.
For trees and shrubs, the mulch layer should be between 2 to 4 inches deep, and extend to a diameter of at least 3 feet. However, the mulch should not be allowed to contact the trunk of the tree (or the stems of
When mulch is allowed to accumulate [or is purposely piled] around the trunk, it prevents natural air-flow around that section of the bark, keeping the mulch-covered portion of the tree damp. That creates an open invitation to disease organisms and insects that can do damage; sometimes to the point of girdling or killing the tree. Also, voles and other bark-chewing animals may be encouraged by a thick layer of mulch.
So, take advantage of the positive attributes of mulching, but avoid the volcano!
<----- Bad. A "volcano" of mulch piled around the tree trunk invites potential damage and decay.
<----- Better. Mulch is kept away from the trunk of the tree, allowing the bark to "breathe".
blog entry and photos by Mark Murphy, CMG