A tree planted incorrectly will at best be under stress and at worst be headed for an early death. Avoid problems by following these tips.
The Root Ball
Before planting, cut through the side of the root ball at four equidistant spots, then cut an X at the bottom. This will prevent roots from circling around and eventually girdling the tree.
Planted too deeply, a tree can develop rot and insect problems. Make sure the root flare—a slight tapering at the base—still shows after planting.
When mulching, think “doughnut,” not “volcano.” The former ensures that mulch is not piled up against the bark, where it can cause moisture and insect problems. It also directs water toward the roots, rather than away from them.
originally posted by Lowe’s