Azaleas are shrubs in the rhododendron family which come in sizes from dwarf varieties under 2 feet tall to near tree heights. They are available in a wide assortment colors as well--ranging from pure white through the palest yellows, pinks, salmon and lavender to rose, fuschia, orange and deep reds. All prefer well-drained, loamy and acidic soil with plenty of organic matter. Many are evergreen in warmer climates, though the majority of azaleas are deciduous.
Determine the pH of your soil using a pH testing kit (or send a soil sample to your local extension service or soil and water offices for analysis). Aim for an acidic soil with a 4.5 to 5.5 pH.
If your soil is too alkaline, add iron sulfate or ammonium sulfate at the recommended levels for your particular situation as shown in the soil test results. (Peat moss is another possible soil acidifier, which also adds beneficial water-retention capability and organic matter to condition the soil.)
Dig a hole to the same depth (and about twice the width) of the pot your azalea was planted in at the nursery.
Work in some organic matter, such as leaves or peat moss, if your soil quality is poor.
Remove the plant from its pot and gently shake off or work loose some of the soil from the container to expose the lower roots.
Place the azalea in the hole, positioning it a bit higher than the level of the hole to allow for settling.
Backfill the hole around the plant's roots and press the soil firmly, but gently, in place.
Water the azalea well to help the soil to settle and to remove entrapped bubbles--which prevent water and nutrients from reaching the plant roots.
Keep the soil well dampened, but not soggy, until the new plant is established. (Adding a bark or leaf mulch around the base will help prevent water loss.)