Bring your azalea tree container to a spot that provides well-drained, moist soil and early morning sun and afternoon shade, or partial shade. The location you choose should allow enough space for the mature size of the azalea.
Dig a hole for the azalea tree at least twice the width of the plant's root ball and the same depth. Water the azalea in the container before planting.
Remove the azalea tree from the container and inspect the root system. Loosen the roots and remove any damaged roots. Make three to six cuts from the top to bottom of the root ball--if the roots are wrapping around the root ball--and then place the azalea in the hole.
Amend between one-third to one-half of the removed soil with organic matter, such as compost, ground pine bark and rotted leaves. Backfill the hole with the amended soil and use your hands to pack the soil in place around the azalea tree.
Add a 2- to 4-inch layer of organic mulch around the azalea to conserve moisture and deter weeds. Keep the area close to the azalea tree trunk clear of mulch.
Water slowly, but thoroughly to remove any air pockets in the soil. Water the azalea tree again in 24 hours, and then weekly for several weeks.