When mulching around a tree, some landscape companies push the mulch up into a mound or "volcano" around the tree trunk. This "volcano mulching" is terrible for the tree because the bark is not designed to be covered like that. When mulch (which is often moist) comes into contact with bark for long periods of time, it creates a more favorable environment for a number of insects and diseases to attack the tree. These insects and diseases would not normally be in such close contact with the bark for such a long time. Also, bark is not designed to have moist mulch up against it like that; the moisture can affect the bark over time.

But mulch does provide a number of benefits. It helps retain soil moisture, keeps weeds in check, helps to prevent erosion, and over time can improve soil structure. But remember not to push the mulch up around the bark--just to the base of the tree with minimal contact.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service