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Native Azaleas
Native Azaleas — natural color in the shade garden
By Joey Williamson, Horticulture Specialist,
Clemson Extension Home & Garden Information Center
1-888-656-9988
CLEMSON – Among the most beautiful of South Carolina’s native flowering shrubs are the native azaleas. Gardeners in all parts of the state can enjoy the spectacular flowers and delightful fragrance of many of these eastern native shrubs.
There are numerous native azalea species in South Carolina, with bloom times from early spring through August. The flower colors range from white to many shades of pink, red, yellow, orange and salmon.
These deciduous shrubs, that is, they lose their leaves during the winter, are members of the genus Rhododendron, which also includes the evergreen azaleas and rhododendrons. Mature plant sizes vary from two-foot tall spreading species to 20-foot tall tree-like shrubs.
The Florida Flame Azalea (Rhododendron austrinum) blooms in early May with orange, yellow or scarlet flowers. This magnificent plant will certainly stop traffic. ‘Dawn at the River’ is a cultivar with tri-colored trusses of yellow, orange and red flowers.
The Piedmont Azalea (R. canescens) is one of the earliest bloomers and begins its show in early April. ‘Camilla’s Blush’ has ball-shaped trusses of soft pink blossoms, and grows to eight feet.
The Flame Azalea (R. calendulaceum) typically has large orange blooms, but again, colors vary widely. ‘Kelsey’s Flame’ is outstanding cultivar with striking yellow and orange flowers, and grows eight to 10 feet tall.
The Sweet Azalea (R. arborescens) has white blooms, dark green foliage and is very fragrant. This June bloomer usually needs relatively moist soil. ‘Gable’s Yellow’ has light peachy-yellow flowers with deep yellow throats. ‘White Lightning’ has a bright white flower with a yellow center. These cultivars will grow six to eight feet tall.
Other native azaleas available include the Coastal Azalea (R. atlanticum), the Pinxter Azalea (R. perichmenoides), the Swamp Azalea (R. viscosum) and numerous cultivars of crosses between our native azaleas. These crosses have added to the many color variations and color combinations naturally present in our native azaleas.
Native azaleas prefer cool, partially shaded sites with rich, moist woodland soil. But exceptions occur— some will tolerate dry woodland soil, and others flourish in what would be considered excessively moist areas.
They can be planted any time of the year, but greater success may be obtained with an autumn planting. However, spring is usually the time these shrubs are found at the garden centers.
From a landscaping perspective, these native species can be grouped by flower color: white, pink or orange. However, considerable variation in flower color occurs within each species, and nurserymen have selected those with the most stunning colors. Recently, more garden centers in South Carolina have offered native azaleas for sale including many cultivars selected for their superior flower color.
Native azaleas prefer acid soils with a pH of around 5.0, and most South Carolina soils are naturally acid. Unless directed by a soil test to add lime to the soil, you should not lime the soil near these plants, because their foliage may become yellow or chlorotic.
When choosing a site for a native azalea, morning sun and afternoon shade will be best. In general, species that flower in June or later may require more shade, as the delicate flowers will not tolerate the hot summer sun. For overall plant health, adequate soil moisture can help compensate for the excessive summer heat.
When planting native azaleas, it’s always best to loosen and prepare the soil in large planting beds, rather than individual holes. One of the best forms of organic matter to incorporate with the existing soil is composted pine bark. These shrubs must be planted at the same level in the soil as they were in the container, or slightly higher if the soil is poorly drained.
Be sure to mulch the plants with three or four inches of bark, pine needles or leaves to help keep the soil cool and to conserve soil moisture. However, the mulch should not be piled against the stem or trunk of the plants. Then be sure to water the plants well to settle the soil. Remember, until a plant is established, it is dependent upon the homeowner for water.
Fertilize native azaleas lightly in the spring and early summer with a well balanced, extended-release fertilizer, such as a 14-7-7 or 10-6-8 azalea and camellia fertilizer. Well-balanced organic fertilizers are also excellent choices for use on native azaleas. Never fertilize the azaleas in the late fall as this may delay dormancy and result in plant injury.
With proper site selection and planting, you will be pleasantly surprised at how well they perform and pleased with their exceptional beauty.
The Clemson Extension Home & Garden Information Center (HGIC) has more detailed information on planting procedures and other woody plants. For information, go to the HGIC website, http://hgic.clemson.edu.
Visit your local Extension on-line at www.clemson.edu/marion
or call us at 423-8285 (8am to 4:30pm – M-F).
Last update4/24/2008
This website is maintained by Marion County Extension.
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