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Journal American Rhododendron Society

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Dr. Glen Jamieson ars.editor@gmail.com


Volume 27, Number 1
January 1973

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Exploring the Color-Range
of the Native Azalea R. calendulaceum

Martha Prince, Locust Valley, New York

R.  calendulaceum
R. calendulaceum (B #12)
Photo by Martha Prince

        I find that many "rhododendron people" tend to scoff a bit at our native "flame azalea", R. calendulaceum. I wouldn't blame them if I had seen only the sprays that turn up in the Species Azalea section of our New York Chapter shows, or those that most nurseries (if they sell them at all) put on the market. The flowers are almost always a quite undistinguished pale orange. However, I was brought up in Georgia, in the lower part of the Blue Ridge Mountains; since childhood I have known the variety of colors and the beauty of this ancestor of the Ghents, the Knaphills, and the Exburys (plants and seeds of R. calendulaceum courtesy, originally of the peripatetic Andre' Michaux). Having become familiar with species azaleas in our shows - which sprays win prizes, and which do not - I am convinced that over the years I have randomly picked many sprays, in the wild, worthy of "Best Species Azalea of Show" anywhere. I, personally, would expect to see such sprays as "Best Azalea of Show" (species or hybrid). Some could defeat any Exbury I know, certainly any we grow in our Long Island garden. R. calendulaceum can be a gorgeous thing!
        This past June my husband and I made a special trip "home" to Georgia, in order to photograph the color-range of R. calendulaceum. June 20th is generally the height of bloom at a favorite spot of mine - part way up Brasstown Bald, the highest mountain in northeast Georgia, or in the state, for that matter. This is in the Chattahoochee National Forest now, and the Forest Service, which should know better, built a huge parking lot right on - not even in - the best stand of "my" azaleas. I often used to picnic under what I later call a "B # 12", by a small stream. Now the picnic place is "six feet under". A Forest Service bus (for 50 cents) picks up tourists at this hideous and enormous asphalt square, for a trip to the elaborate tower now located on top of the mountain. Once there was only an open-work steel fire tower there! The vista from the summit is of pile after pile of blue mountains and a scattering of silver lakes.
        The azaleas on the mountain probably start at about the 3500 ft. elevation, and go to the parking-lot altitude of about 4300. The peak is at 4784, but the mountain is a "bald", the Southern name for those with treeless summits. R. calendulaceum grows at lower altitudes, too, of course; the hill in back of my childhood home (elevation less than 1800 feet) had a sprinkling of them. However, courtesy of the intrusion of "civilization", only the still wooded mountains have large groups. One stand of huge old plants (20 feet in height, and more) quite near my home seems to have disappeared in the last three or four years, - I suppose to new houses, or just to the passion for "clearing out the woods". At the lower altitudes the blooming date of the azaleas is earlier, of course. The higher one gets, the later spring comes.
        We had only one afternoon to spend at Brasstown Bald, one notebook, two rolls of Ektachrome film, and a good camera. One of the forest rangers, Jesse King, became interested in my rather frantic attempts at writing in a large flapping notebook, as the wind was gusting up to 50 m.p.h. He drove us around a bit in his truck, on a jeep track. Mr. King was not a botanist, (he called Kalmia latifolia "ivy", and R. nudiflorum "honeysuckle," in the Southern Country way), but he had a "big red 'un" he wanted to show us. Unfortunately, it was not the red at all, but an Orange we had already photographed. We missed the true reds entirely, and the soft yellows were fading; we got no bright, clear yellow, either, - and there definitely is one. However, we found and photographed twelve distinct color variations, all within a few hundred square yards. We took a leaf and a flower of each, and I catalogued them and keyed them to the film numbers as best I could (the wind being as uncooperative as it was.) The Forest area closes at 6:00, but Ranger King said we were welcome to stay until we finished.
        Frederick Lee listed R. calendulaceum in the Austrinum-Prunifolium alliance. The azaleas in this group are all diploid except for R. calendulaceum, a tetraploid. If a natural hybrid occurred at some time in the past, and is polyploid, it is still classified as definitely R. calendulaceum. This azalea, while considered a species, is usually called a "derived species". The R. austrinum, which might have introduced a yellow strain at some time in the past, when the geographic distribution may have been different, is nowhere near. R. austrinum is a north Florida and coastal-plain plant in Georgia and Alabama (hundreds of miles from Brasstown Bald). R. bakeri (the "Cumberland azalea") could, geographically, and as a mountain azalea, have brought in some red. That plant is not familiar to me, and is lower in mature height than is the red form of R. calendulaceum I know. R. speciosum, another possible diploid source of red, does not grow in the mountains, although it is listed as growing on the Piedmont Plateau, and extending to the coast. The Plateau begins 40 to 50 miles from Brasstown Bald; it is the geographic area immediately after the Blue Ridge, in the southeasterly direction. The only azaleas actually blooming in "my" area on the mountain at the same time as R. calendulaceum are R. arborescens, and just possibly R. viscosum. Although I have not seen R. viscosum for certain on the mountain, it grows in profusion at a lower altitude within 15 or 20 miles. Of course. I could be mistaken, and thought my white azaleas on the mountain were R. arborescens when they may have been R. viscosum var. montanum. The white azalea flowers on Brasstown were lovely, "star-like", and larger than the R. viscosum with which I am familiar. As we were on a Calendulaceum Hunt we did not study the white azaleas, and only took a few pictures; there are not very many plants there. We saw two varieties of (supposed) R. arborescens; one pure white, and one distinctly pinkish, by virtue of its pink tubes, buds, and filaments. These could easily have been hybridized with R. calendulaceum by any wandering bee. Mr. Lee, however, said the pinks in R. calendulaceum most likely came from R. viscosum (the Arborescens-Serrulatum alliance, in his classification), and he knew far more than I do.
        If some of the dozen R. calendulaceum colors we catalogued are diploid (I have made no microscopic study, and must await assistance on that point. I am not a geneticist.) of course they are not R. calendulaceum at all. But then - what are they? They seem too special and distinctive not to have a name of their own! If polyploid, I am happy to leave them all as R. calendulaceum, although I would like to see some listed as var. so-and-so. If they are not R. calendulaceum, why not at least R. calendulaceum x (blank), var. (blank)? My numbers B # 10 and B # 12 below, for instance, are too spectacularly good to be anonymous.
        My list misses. as I mentioned, the clear yellow and the clear red. Here are the dozen we documented. I had no color chart along (neither the Royal Horticultural Society, nor Mansell Nickerson), and had to rely on "artists'" language for color (I do botanical drawing and painting). Sun and shadow make such a tremendous difference anyway; it is difficult to pinpoint a flower-color exactly.

B # 1 Soft, creamy yellow with a tinge of orange on the upper petal. Large flowers (to 2")
B # 2 A good medium-to-light orange (probably "cadmium orange, light", on a tube of watercolor), with a definite yellow tinge to the upper petal. Large flowers (2").
B # 3 A more brilliant and deeper orange than B # 2. The leaves were heavily veined, and almost ruffled.
B # 4 A light orange tinged with pink on all petals. The upper petal has a yellow stain. Flowers large (2").
B # 5 Similar to B#1, but a little paler in color. Individual florets much smaller (1") and more florets to the truss.
B # 6 A brilliant, deep orange-scarlet. Red filaments, yellow anthers. Leaves quite ruffled, and with red veins on the underside.
B # 7 A lighter but redder orange than B#6, and with similar leaves (red veins).
B # 8 Good clear orange, with a yellow center and a reddish edging on all five petals. This was the only plant we found with this pattern of coloration. Red filaments, yellow anthers. Foliage was unusually glossy.
B # 9 Salmon-orange. Absolutely no shading or blotch of any color. Bright red filaments. Leaves elliptical with mucronate apex.  This one had been tagged by someone in the biology department at Wake Forest College.
B # 10 Medium salmon-pink, almost seeming striped in deeper tones down each petal. Yellow-orange blotch on upper petal. Filaments and anthers, pink. Leaves narrow, smooth-edged, longer and more pointed than any of the other plants (oblanceolate). The size of the individual sprays and the grace of plant habit are very fine, although the florets are not especially large.
B # 11 A paler but clearer salmon-pink than B # 10, and the blotch yellow. Filaments pale pink to white at base.
B # 12 A lovely, clear, soft pink, with the upper petal pure white (tipped in pink at the very top) and blotched in a clear yellow. Tube, a deep pink. Filaments, pale pink, with anthers a deep pink. Leaves small, neat, almost round, - or at least a wide obovate.

        I felt our few hours of azalea study on "my" mountain were most rewarding, and certainly fun. I am glad to say our photographs turned out beautifully, although the color matches do not always seem exact. We have yet to find "the" film for perfectly true flower photography, at least if we are photographing different colors and different lighting. I usually draw or paint from nature, but I can do it from our own photographs if I have seen and studied the flower (and made some notations). It would be impossible to do twelve drawings in one day! I suspect I will be working on at least a few of these next winter, when there are only "snow flowers" in the garden. That will bring back June on a lovely mountain.


Volume 27, Number 1
January 1973

DLA Ejournal Home | QBARS Home | Table of Contents for this issue | Search JARS and other ejournals