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Archive date:  April 19, 2001

Planting and Caring for Azaleas

The secrets to healthy azaleas

Hybrid evergreen azaleas are among the most popular flowering shrubs used in Tennessee homescapes. When installed properly they provide a brilliant floral display. The key to healthy azaleas is in the location and soil preparation.

Azaleas perform best when placed in partial shade. This can be a woodland area that receives filtered sunlight through deciduous trees or through pine trees. (Pine trees help to maintain an acidic soil.) They can take some morning sun, planted on the north side of a house or hedge planting. Keep in mind that some azaleas may reach heights to 10 feet. Measure the area the azaleas will be placed before selecting a variety.

Soils preparation:
Azaleas are healthiest in an acidic soil with a pH of 4.0 to 6.0. The soil must be loose, well-drained, and contain lots of organic matter. Performing a soil test is the best way to insure proper soil acidity. The addition of peat moss, leaf mulch, old sawdust, or compost aids in making the soil more acidic, and adds plenty of organic matter. A 50-50 mix of sand and organic matter is ideal.
If the bedding area is poorly drained it would be best to select a plant better suited for the area, such as Itea, or swamp jasmine. Azaleas do not like their feet wet and will usually fall victim to Phytopthera, a soil-borne fungus, in such areas. Raised beds may be constructed to improve drainage; they should be at least 8"-12" above ground level.
When tilling in the organic matter include a slow release fertilizer with a material that increases soil acidity, such as ferrous sulfate, copperas, iron chelate, or finely ground dusting sulfur. Apply the fertilizer at rates based on the soil test or at rates specified on the fertilizer label.

Care after planting:
Azaleas have a relatively shallow and extremely fibrous root system. A strict watering schedule is essential during the growing season. Overwater can be detrimental to azaleas. They only need the equivalent of 1 inch of rain every 7 to 10 days. It is important to continue watering during late summer, through fall, until winter rains begin.
Because of azaleas shallow root systems, they are easily damaged by cultivation such as hoeing or raking. Be extra careful if planting annuals around the azaleas.

Other Resources
Pruning Azaleas - Delaware Cooperative Extension
Azalea Pests and Diseases - Ohio state University Extension