I have seen mounds of mulch around trees throughout town. How deep should the mulch be around my trees and what kind of mulch is best?
Mulch is useful for controlling weeds, retaining soil, protecting the roots and generally increasing the health of the tree. It is best to mulch with wood chips or other coarse organic material. Mulch should never touch the tree’s bark and never be piled higher than 3 to 4 inches deep. Mulch that is too deep or directly touching the trunk of the tree decreases the exchange of oxygen and carbon dioxide which can lead to fungal and bacterial diseases. Mulch should not be allowed to become compacted, and before any new is applied, should be loosened and aerated. A properly mulched tree is surrounded by a “donut”, not a “volcano”.