Benefits of proper mulching:
- Retains moisture around the plant
- Maintains stable soil temperature
- Smothers weeb growth
- Provides nutrients through decay of the mulch material
- Protects from injury by equipment
- And it looks terrific!
But as beneficial as mulch is, too much can be harmful. The term "mulch volcanoes" has emerged to describe mulch piled up around the base of trees. Excessive mulch against the base keeps moisture in direct contact with the bark causing, general decline, leaf drop, fungi & premature death.
Proper Mulching:
Apply mulch starting 6 inches from the base of tree & working out to desired diameter. Depth should start at 1inch at the inner circle, increasing to no more than 4 inches at the outer edge of the circle. If mulch is already present, check the depth & fluff it up before adding fresh.
What to Do with Improperly Mulched Trees & Shrubs
If mulch is piled against the stems or tree trunks, pull it back several inches so trunk and root crown are exposed. Remove excess mulch using a shovel, trowel etc. while taking care not to damage the trunk. New mulch can than be applied properly.
Annual Maintenance
Additions should be made only to maintain proper depth. If you just want to refresh the appearance, fluffing the old mulch before adding new will prevent it from forming a hard surface that deflects water rather than retaining it. Removal defeats the purpose, which is to decay and mix with the soil.