Organic mulch should be applied around the tree to a depth of two to four inches. Monitor mulched areas during the winter to detect any rodent activity. Mulch should be renewed as needed to keep a good depth. Use wood chips, bark or some other natural material as mulch. Avoid using rocks or plastic sheeting.
Rocks cause soil compaction, and plastic sheeting suffocates root systems.
Woven weed barrier fabric can be effective at reducing weed competition. It allows moisture and oxygen to enter the soil. It does not, however, add organic matter to the soil or reduce compaction like a natural mulch. Mulch should be spread a foot or more from the base of the tree in all directions. Mulch can be placed directly on grass when mulching established trees.