Foliage: Evergreen broadleaf
Height: 3 to 8 feet (depending on cultivar)
Spread: 4 to 8 feet (depending on cultivar)
Shape: Upright, spreading
There are hundreds of evergreen azalea cultivars which vary in hardiness, size, form, flower color, time of flowering, and foliage. The primary attractive feature of azaleas is the very attractive and showy flower display in spring.
Zone: 5b to 9 (depending on cultivar)
Light: Partial shade
Moisture: Moist to average
Soil Type: Sandy to loam to clay loam
pH Range: 3.7 to 6.5
Suggested uses for this plant include massing, border, and foundation plant.
Plant azaleas in a site that has afternoon shade to protect plants from the hot summer sun. Do not plant in poorly drained or heavy soils. Plant in well-drained, acid soil.
If drainage is a problem, plant in raised beds, or install drainage tile to drain water away from plants. Evergreen azaleas should be primarily selected on the basis of their hardiness (tolerance to low winter temperatures), so consult local garden center personnel to determine what azaleas are suitable for your plant hardiness zone.
Spread a good, organic mulch to control weeds, maintain soil moisture, and protect tender shallow roots.
To maintain form and size, pinch off soft, new shoots of vigorous growing plants soon after flowering.
Iron chlorosis (leaves turn yellow between veins, but veins remain green) is a problem in high pH soils.
Some common insect problems are the azalea lacebug, aphids, leaf miners and tiers, scale insects, and whitefly.
Common diseases are Phytophthora root and crown rot, Ovulinia petal blight and powdery mildew.
Consult local garden centers, historic or public gardens and arboreta regarding cultivars and related species that grow well in your area.
`Pink Pearl' has pink flowers.
`Flame' has orange-red flowers with a dark blotch.
`Snow' is the most reliable of the white- flowered Kurume hybrids.
`Girard's Scarlet' is a low-growing azalea with red flowers.
Most evergreen azalea cultivars are hybrids. The most important cultivar selection criterion is hardiness. Thus, before purchasing an azalea, you must determine if a particular azalea cultivar is hardy in your area. For information on particular azaleas, consult the Azalea Society of America (http://www.azaleas.org/index.html) and the American Rhododendron Society (http://www.rhododendron.org/searchazalea_intro.htm). U.S. azaleas are deciduous are will not be discussed in this publication. Azaleas can be differentiated from rhododendron in that azaleas have small, relatively thin leaves, flowers with 5 or 6 stamens (rhododendron have 10), funnel-shaped flowers (rhododendrons have bell-shaped flowers), and small leaved rhododendrons have of scales on the back side of the leaves whereas azaleas do not. Flowering time varies. By combining early, mid-season, and late bloomers, the seasonal show can be extended dramatically.
This material was developed by Carol Ness as part of the Interactive Design and Development Project funded by the Kellogg Foundation.
Virginia Cooperative Extension materials are available for public use, re-print, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Alan L. Grant, Dean, College of Agriculture and Life Sciences; Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; Jewel E. Hairston, Administrator, 1890 Extension Program, Virginia State, Petersburg.
May 1, 2009