Azaleas, perennial shrubs valued for their large, dramatic flowers, grace the lawns and gardens of homes across the world. Found wild on every continent except Africa and South America, azaleas thrive in USDA hardiness zones 4 through 9 and grow best in the temperate environment of the southern and central United States. The plants require almost no care to survive, though pruning and regular feeding promotes rapid growth and flower formation. With more than 3,000 cultivars of azalea available, these shrubs add color and interest to any landscape year round.
Plant azalea flowers during spring after the danger of frost passes in a location that receives filtered sunlight. Prepare the planting site by spreading a 2-inch layer of composted pine bark over the area. Use a garden tiller to incorporate the bark into the soil. Space azalea flowers 24 to 30 inches apart.
Spread a 2- to 3-inch layer of mulch over the soil surrounding azaleas to maintain an even soil temperature, discourage the growth of weeds and conserve moisture. Keep the mulch in place from early spring until mid-fall. Allow at least 3 inches between the mulch and the plant to minimize the risk of fungal disease.
Water azalea flowers twice per week during the first year of growth to provide adequate moisture. Reduce the frequency of watering to once every week thereafter. Soak the soil to a depth of 6 to 8 inches at each application. Pour water directly over the soil to avoid dampening the foliage.
Feed azaleas three times a year, once during March, once during May and again in September. Use a 6-6-6 NPK fertilizer to provide optimal nutrition. Follow the manufacturer's directions for the best results. Water lightly prior to feeding to prevent potential root injury.
Prune azalea flowers during spring, immediately after flowering has ended. Cut back any overgrown limbs and remove dead or diseased growth using pruning shears to improve the plant's health and appearance.
Renew overgrown azaleas by cutting them to 6 to 12 inches above the soil level during late winter, just before new growth resumes. Cut back new shoots by about 1 inch once they reach 6 to 12 inches long.