Azaleas are a variety of rhododendrons. They have small leaves and can grow different colored flowers, depending on what kind of azaleas they are. Azaleas can be either evergreen or deciduous shrubs, but evergreen azaleas are more popular, especially in Tennessee. Tennessee consists of USDA hardiness zones 7 and 8, which are both conducive zones for growing most azaleas.
Select an azalea that is appropriate for your Tennessee climate. Gardeners in zone 7 (northern and mountainous areas) should select a hardy azalea such as Korean azaleas and gable hybrids. Gardeners in zone 8 can select any kind of azalea.
Prepare your planting site. Azaleas prefer well draining soil, so adding a couple inches of humus such as peat moss, rotted sawdust or compost to the soil bed will help your azaleas thrive. They can tolerate most pH levels (4.0-7.0), but prefer a pH between 5.0 and 5.5. If desired, you can test your soil with pH test strips available at most local nurseries and amend your soil with either lime (to raise pH) or sulfur (to lower pH).
Plant your azaleas. Dig a hole that is three times as wide and just as deep as the azalea’s current container. Take the azalea out of the container and set in the hole. Back-fill the soil, which should be amended from step 2 and tamp it down well to remove any voids in the soil.
Space azaleas depending on their kind. For example, crimson azaleas should be spaced about 2 feet from one another while encore azaleas should be spaced 4 feet from one another. If desired, you can plant azaleas closer together so it looks nicer for the first couple of years, and then transplant every other one at a later time.
Mulch your azaleas. In Tennessee, where summers can get extremely hot, especially in zone 8, and winters can be quite cold, especially in zone 7, mulch is great for insulation to keep soil temperature more consistent all year long. It also helps retain moisture and as it decomposes, it adds rich organic matter into the soil. Mulch about 3 inches of organic matter such as bark, peat moss or pine needles.
Fertilize your newly planted azaleas applying about 1 tablespoon per plant of a fertilizer labeled 12-6-6. Water your plants well after fertilizing.