When landscaping around a recently planted tree, lay wood mulch about four inches deep at the base of the tree. The mulch will help control weeds and help the soil retain moisture. However, do not mound dirt at the highest point. This is a common mistake and can result in water running away from the tree.
Before laying mulch, it is best to install an edging to separate the mulch from the lawn. A paver or stone edging, at least four inches wide, is an attractive option. When installed correctly, the edging will help separate the mulch from the lawn and provide a path for a mower wheel when mowing the lawn. This also will help eliminate weed whipping. Also, keep in mind how large the root structure of your tree will become. Anticipating and accommodating this growth will help prevent future repairs to your edging.