As spring encourages gardeners to mulch around their trees, it is not wise to mulch too generously. Indeed, mulch should never be piled up against a tree’s bark. Mulching in a “volcano” shape can render the tree more susceptible to fungus, insects, and rodents.
Instead, mulch in a “donut” shape. Keep mulch six inches from the trunk and mulch out as far as the branches above. Keep the mulch two to four inches thick. Every spring, break up the old mulch and add new to maintain thickness. The best mulch to use is recently chipped wood because it doesn’t compact quickly.
Poperly applied mulch will benefit a tree by: preventing soil compaction; retaining moisture where surface roots can get it; keeping lawn equipment from damaging the trunk; moderating ground temperature; reducing competitive vegetation; and providing nutrients as it breaks down.
Ron Slinn
Vice Chair, West Windsor Shade Tree Commission
