You have probably seen them around town – mounds of mulch piled high around the base of trees. It is a practice that seems to be on the rise. However, it is bad for the plants. Mulch is used in the landscape to retain moisture, maintain temperature and prevent weeds. Although applying some mulch to your landscape is good, applying too much can be harmful to your plants.
Some of the effects of mounding mulch against the trunk or stems of plants include the increase in the likelihood of disease. Fungus and bacteria can proliferate in the wet environment that mulch can create. These diseases can penetrate the inner bark and ultimately starve the plant resulting in plant death. Typically, applying mulch at a depth of two to three inches is all that is needed. Just be sure to leave some room between the mulch and the base (trunk or stem) of the plant.