Mulch Wide, But Not Deep
Mulch holds moisture, moderates soil temperatures, reduces competition from grass and weeds, and prevents lawn mowers and trimmers from nicking the trunk. Mulch also helps insulate the ground, keeping it cooler in the summer and warmer in the winter. Make a 3-ft. (or larger) circle of mulch 2 to 4 in. deep around the trunk. But don't mulch too deep. This can create surface drainage problems and deprive roots of oxygen. Keep the mulch 3 or 4 in. from the trunk to avoid disease, rot and pest problems. Mulch, like other organic matter, can have bacteria and fungus, which can spread to the tree and harm or even kill it. Some good mulch choices are shredded bark or composted wood chips. Don't use woven or plastic landscape fabric or other weed barriers underneath the mulch. These can cause major problems later on as seeds grow roots down through these materials and anchor themselves into the barriers.
Leave a Protection Zone
When you plant your tree, leave a circular area around its trunk for a small flower bed. The flowers are not just attractive; the bed also establishes a buffer zone so that lawn mowers and trimmers can't nick or cut the bark. (String trimmers are a young tree's worst enemy!) For added protection, install vinyl edging to keep grass out of the bed.