JARS v55n2 - Deciduous Azaleas: Springtime in the South

Deciduous Azaleas: Springtime in the South
L. Clarence Towe
Walhalla, South Carolina

Taxonomists now generally agree there are fifteen species of deciduous azaleas in North America. The simple mnemonic device of 1 + 2 + 3 + 4 + 5 = 15 makes it easy to remember them, though identifying them in the field may be more of a problem. To do that, knowing where you are - an increasing problem for some of us - helps considerably.

One fragrant West Coast species = Rhododendron occidentale , the western azalea.

Two non-fragrant pinks = Rhododendron canadense and R. vaseyi . These two are members of subgenus Pentanthera , section Rhodora (formerly subseries Canadense [Davidian]) and will not hybridize with each other or with any of the other thirteen species, which are members of subgenus Pentanthera , section Pentanthera , subsection Pentanthera (formerly subseries Luteum [Davidian]).

Three fragrant pinks = Rhododendron canescens , R. periclymenoides and R. prinophyllum .

Four fragrant whites = Rhododendron alabamense , R. arborescens , R. atlanticum , and R. viscosum . At one time R. coryi , R. oblongifolium and R. serrulatum were recognized as separate species in this group. Chemical analyses now indicate they fit within the parameters of the highly variable, sticky-tubed R. viscosum , which is still referred to in some areas as the catch-fly azalea. Having sticky viscous tubes, however, is a trait shared by several members of the subsection Pentanthera , especially R. arborescens and R. atlanticum .**

Five reds, oranges and yellows = fragrant Rhododendron austrinum , R. calendulaceum , R. cumberlandense , R. flammeum , and R. prunifolium .

Of the fourteen East Coast species, Rhododendron alabamense , R. atlanticum , R. austrinum , R. canescens and R. flammeum can be loosely classified as early bloomers, though depending on altitude, latitude and microclimate, other species also bloom early in some places. In years past several individuals rescued a large number of selections of these species and their hybrids from the wild. Many have been passed along from garden to garden, their value long recognized by the more astute collectors.

Some can be found in catalogs and are well worth seeking out. The following is not a comprehensive list but is a guide to some of the older tried-and-true selections for early color in USDA zones 6-9. As a group they are heat tolerant, easy to grow and probably more cold hardy than listed.

The Early Species
In its better forms, Rhododendron alabamense is perhaps our most elegant deciduous azalea. It typically has yellow-blotched fragrant white flowers with the scent being described by some as resembling lemons and by others as resembling perfumed talc. It is interesting that no selections of this species were named by the early collectors.

Rhododendron atlanticum is a low-growing stoloniferous species that has a low, rambling growth habit in the shade. In full sun it can be very dense. It has light to dark blue-green leaves covered with a glaucous, waxy white powder that partially dissolves as the season progresses. Its medium to large white flowers are very fragrant and are occasionally flushed pink.

Rhododendron austrinum , a colorful, fragrant early showoff that comes in shades of pale yellow to vivid yellow to yellow-orange, is a good-doer that should be in every garden. Some forms have yellow tubes, while others have contrasting light red to strawberry red tubes. Due to fragrance, vigor, color and rootability, more selections were made from this species than from the other four.

Having fragrant white to pale pink to medium pink flowers with light to dark pink tubes, Rhododendron canescens has the widest distribution of any deciduous azalea. In its better forms it is a good plant, yet few superior cultivars have been named. It was described by one authority as being "a valuable plant for the woodland setting," a kind way of saying that it isn't the most interesting plant around. One of the reasons is that the petals are usually narrow with re-curved margins, giving the flowers a somewhat frazzled, jumping-jack look. Vivid pink forms exist but when examined closely are usually found to be R. canescens x R. flammeum hybrids.

Rhododendron flammeum is a non-fragrant extrovert that blooms soon after R. austrinum and R. canescens . It comes in shades of clear yellow, to orange, to bright red. Several cultivars of this heat-tolerant species have been propagated over the years, but it has never gained the recognition it deserves.

The Azaleas of Aaron Varnadoe
It is likely the late Aaron Varnadoe of Colquit, Georgia, collected, hybridized and propagated more superior varieties of early-blooming deciduous azaleas than any of his counterparts. A farmer early in life, he later opened a nursery specializing in cutting and seedling grown Rhododendron austrinum , R. canescens and R. flammeum . He later began hybridizing between the three species and grew countless thousands of seedlings over the years. From these seedlings he made selections based on rootability and unusual colors. In addition to the cultivars listed below, his garden still contains a large number of unnamed selections. His son David recently numbered and photographed the 160 plants in his father's collection and is propagating the better cultivars.

'Varnadoe's Apricot'* is a R. austrinum x R. canescens hybrid with fragrant pinkish orange flowers with red tubes. It is easy to root and grow and has the vigor and appearance of R. austrinum .

'Varnadoe's Buttercup'* is a clear medium yellow R. austrinum with yellow tubes. Winter buds are large with pearlescent bud scales, typical of this species.

'Varnadoe's Moonbeam'* is an early-blooming yellow R. austrinum with light red tubes. Like many deciduous azaleas it opens bright yellow and fades slightly as the season progresses.

'Varnadoe's Orange'* is a R. austrinum x R. flammeum hybrid. The mildly fragrant flowers have red tubes and orange petals edged in yellow. The plant has the vigor and rootability of R. austrinum .

'Varnadoe's Phlox Pink'* was sold for years as "#1 Pink Canescens" by Mr. Varnadoe. The buds and tubes are bright pink on the outside and the flowers are light, clear pink when fully open, with the color at its best on well-established plants. It has attractive dark, semi-glossy leaves that are held in a conspicuous upright position. The plant grows in an unusual narrow upright vase shape and refuses to sucker at its base, which keeps its light gray trunks exposed.

'Varnadoe's Red'* is Mr. Varnadoe's best selection of R. flammeum , though he grew and sold several forms over the years. The old plant in his garden is labeled "Special Red," which tells us it must have been one of his favorites.

'Varnado''s Salmon'* is a fragrant pastel pink and yellow R. canescens x R. flammeum hybrid that has unusual light brown overtones when viewed from a distance.

'Varnadoe's Snow White'* is a fragrant R. canescens , or R. alabamense x R. canescens hybrid, that is very white. While a bit slow to set buds as a small plant, it becomes very floriferous when established and is one of the best pure whites available.

Other Collectors and Selections
'Choice Cream' is probably the best selection made by the late Fred Galle, noted azalea and holly expert. It resulted from a cross in which he successfully combined the vigor of R. austrinum with the small foliage and clump-forming habit of R. atlanticum . The fragrant flowers are light yellow with gold blotches and pink tubes. The leaves are small and rounded and the wood is slender. It forms a dense clump to 6 feet (1.8 m) in height.

'Coleman's Early Yellow'* is a R. alabamense x R. austrinum hybrid that has light lemon yellow flowers with white throats and pink pistils. It blooms very early in March in the South and has the vigor and rootability of R. austrinum .

'Coleman's Sunshine'* has fragrant bright yellow flowers and is probably a R. alabamense x R. austrinum hybrid. It is a compact good-doer but lacks the vigor found in most R. austrinum hybrids.

'Escatawpa'* is another choice selection of R. austrinum . If only one cultivar of this species could be grown, many would choose it. Found by Bill and Tom Dodd near the Escatawpa River in southwestern Alabama, it has fragrant gold flowers with wide petals and light red tubes. It is vigorous to 10 feet (3 m) and is easy to root and grow.

'Marydel' doesn't have its origins in the Deep South but has earned its place on any list of early good-doers. Its foliage, growth habit, fragrance, flower shape and size are typical of its R. atlanticum parentage, while the strawberry red tubes and pink stripes on the petal backs hint at its R. periclymenoides ancestry. It was selected and named by Polly Hill from a group of stable hybrids found on the Choptank River near the Maryland-Delaware state line.

'Millie Mac' is a selection of R. austrinum that may be the only deciduous azalea in cultivation with picotee flowers. It was found as a limb sport by Floyd Mc-Connell in Escambia County, Alabama. The gold flowers have narrow ⅛-inch (0.3 cm) white margins while the tubes, new stems and leaf petioles are red. Suckers from its base will occasionally revert to small gold flowers with red tubes.

'My Mary' was hybridized by the late George Beasley. Named for his wife, it is a seedling from a cross between R. austrinum and a Choptank azalea. It has fragrant medium yellow flowers on a compact plant that shows considerable Choptank influence. It is easy to grow and seldom exceeds 5 feet (1.5 m) in height.

'Riefler's White'* is an unusual form of R. austrinum that originated as a bud sport. Found by Steve Riefler in Florida, the plant has typical foliage but small fragrant white flowers with gold blotches. As with 'Millie Mac', suckers from the base of the plant occasionally revert to small gold flowers with red tubes.

'Choptank Rose'* is another of the late George Beasley's many selections and may be his best. It is a hybrid between a Choptank azalea and a red R. flammeum . The plant is compact and upright to 4 feet (1.2 m) with semi-glossy foliage. The fragrant flowers are rose with yellow blotches. It is heat tolerant and grows well in heavy clay soils. The name was recently changed and it is now a member of Transplant Nursery's trademarked Maid in the Shade series.

'Snowbird' is a R. atlanticum x R. canescens hybrid from the Biltmore Estate Collection in Asheville, North Carolina. It has fragrant white flowers with a hint of pink in the tubes and pistils. The leaves are dusty blue-green and the plant has a dense growth habit.

* Name is unregistered.

** The populations of R. alabamense in South Carolina were recently reclassified as a new species, R. eastmanii . If this stands, the fragrant white group will have five members.

Clarence Towe is a member of the Azalea chapter.