A parent of many well-known cultivars (including the PJM hybrids), these small to medium-sized rhododendrons are outstanding ornamental plants in their own right. They are selections of a distinct race of Rhododendron minus var. minus from the the mountains of western North Carolina. These evergreen shrubs bear rounded trusses of rosy purple, pink, or white flowers from early to mid-spring. The wide-flaring funnel-shaped blooms often have a contrasting greenish-yellow blotch on...
The Catawba group of rhododendron is comprised of variable hybrids of Rhododendron catawbiense. They are best known for their large, showy clusters, or trusses, of tubular, broad bell-shaped flowers that come in shades of purple, mauve, pink, red and white. These medium to large, dense, broadleaf evergreen shrubs have large, glossy, dark green leaves that can suffer from sun and wind damage if too exposed in the winter months. Most rhododendron thrive in sites with part shade and moist, acidic, highly...
(Chisolm-Merritt Hybrid Azalea)
Bearing pink or red flowers in early to mid-spring, these hybrids were developed by Julian J. Chisolm in the 1930s and were later released by Dr. E. I. Merritt. Most include the hardy East Asian azalea Rhododendron yedoense variety poukhanense as a parent. The result is a group of hardy, compact, broad-spreading hybrids with oval, dark green, hairy leaves and clusters of showy flowers. Many bear hose-in-hose blooms (with two "stacked" whorls of petals). The broadly funnel-shaped...
(Coolidge Hybrid Azaleas)
These evergreen azaleas were introduced by Coolidge Rare Plants of Pasadena, California. Most are of the Kurume type. These hybrids bear colorful broadly funnel-shaped flowers on dense compact plants.
These azaleas prefer partial shade and highly organic acid soil that is evenly moist but well-drained. Plant them shallowly and mulch well to conserve moisture and suppress weeds. They do best in warm summers but require some winter cold for good growth. Do any necessary pruning directly after...
Developed in the 1920s and 1930s by Charles O. Dexter of Massachusetts, these large hardy evergreen rhododendrons have several Asian and American species in their lineage, including R. fortunei and R. catawbiense . Dexter Hybrids typically bear generous rounded trusses of large, often fragrant, funnel-shaped flowers in mid- or late spring. The blooms may be white, pink, red, purple, lavender, or creamy yellow. The blooms often bear prominent blotches or speckles....
(Endtz & Co Hybrid Rhododendron)
L. J. Endtz of Boskoop, Holland, developed a number of rhododendron hybrids in the early twentieth century that are still widely planted today. Their wide-flaring funnel-shaped flowers are borne in large rounded trusses in spring. The red, pink, purple, or white blooms often have a contrasting blotch on their upper lobes. The upright rounded plants have large leathery leaves that are often glossy dark green. Among the best-known Endtz Hybrids are 'Antoon van Welie', 'Doctor Arnold W. Endtz', 'Louis...
Gerald L. Klingaman
(Gable Hybrid Azalea)
Developed mostly by Joseph Gable of Stewartstown, Pennsylvania, these hybrid evergreen azaleas include some of the hardiest available, thanks to the contributions of Rhododendron yedoense var. poukhanense and R. kaempferi to their pedigree. Gable Hybrids are also tolerant of heat and drought. They have an extended flowering period and are reliably evergreen in the winter.
The compact, rounded to upright plants have small, shiny, elliptic to oval leaves....
Gerald L. Klingaman
(Girard Hybrid Azalea)
Renowned for their cold hardiness, these compact evergreen azaleas were bred at the Ohio-based Girard Nursery. They are also noted for large blooms on compact disease-resistant plants.
In spring, they put forth large, often ruffled flowers that can be red, pink, fuchsia, salmon, white or yellow. The abundant, usually funnel-shaped flowers cluster near the ends of the branches. The flowers are single, double, semi-double or hose-in-hose (two "stacked" sets of petals). Their small oval glossy...
Tim McCabe, USDA/ARS
(Glenn Dale Hybrid Azalea)
Comprising more than 400 cultivars, the Glenn Dale hybrid azaleas were developed from the late 1920s through the 1940s at the United States Department of Agriculture’s Plant Introduction Station at Glenn Dale, Maryland. This breeding program was initiated by Benjamin Y. Morrison, the first director of the United States National Arboretum. These relatively cold-hardy evergreen azaleas are complex hybrids involving many Asian and North American rhododendrons.
These small to medium-sized shrubs...
(Greenwood Hybrid Rhododendron)
Bred to thrive in the mild climate of the coastal Pacific Northwest United States, these evergreen azaleas were developed after 1960 by Bill Guttormsen of Canby, Oregon, They are the result of crosses between Gable, Glenn Dale, Kurume, and other hybrids. Greenwood Hybrids bear clusters of funnel-shaped flowers on dense compact plants in spring. The funnel-shaped, often ruffled flowers come in a wide range of colors and may be single, semi-double, double, or hose-in-hose (with two superimposed sets...