Rhododendron chapmanii: An American Survivor
Charles S. Hunter
It seems somewhat ironic that rhododendron enthusiasts in the Pacific Northwest seem to be able to grow just about any hybrid or exotic Asian species, yet this same environment is the native home to only one evergreen rhododendron and a single native azalea species. On the other hand, we in the Southeast find several different evergreen rhododendrons in the wild, along with some 14 native azalea species, but we are more restricted in the rhododendrons that do well here, due in large part to our extremes of temperature and irregularly dry summer periods. In the Atlanta area where I live, when experimenting with new plants, I am much more likely to lose one to the summer climate than to the winter cold, even though this area is in the Upper Piedmont at about 1,000 feet elevation, just south of the foothills of the Appalachian Mountains.
It would appear to defy logic even more that an evergreen rhododendron would grow in the gray sand of the blazing hot coastal plain of northern Florida, but Rhododendron chapmanii is found in the wild no further north. I have visited the three known populations of this rare and fascinating plant within the last 12 months.
Most Isolated Population
By far the smallest and most geographically isolated of these locations is within the Florida National Guard post at Camp Blanding in the northeastern part of the state. This area is also including in a larger federally protected Wildlife Management Area. I attended a seminar near Jacksonville last November and was able to make a small diversion on my way home to inspect the habitat. The plants grow between two old roads in a wooded area less than an acre near abandoned World War II military housing. The extensive grading and construction at Camp Blanding in the 1940s killed most of the rhododendron population, and these survivors actually resprouted from an area which had been bulldozed and graded with no regard to the plants and all.
While I was inspecting the area, a burly MP pulled his jeep behind my car and asked me what I was doing there. Seeing the I had a camera rather than a shovel, he become friendly and proudly revealed the he had been the discoverer of these plant when he had noticed them in bloom only a couple of years before! I certainly had no inclination to burst his bubble, and I could not image that the rhododendrons could have better protector than this gentleman, so I declined to take issue with him about his "discovery". The federal Wildlife Management Area people are also very aware of the rhododendrons, so suffice it to say that the people at Camp Blanding know about these plants and don't much want folks messin' with 'em!
The largest population is located in the middle panhandle within 75 miles of
Tallahassee. This habitat of less than 10 square miles is certainly not solid with the plants, but consists of a few large to medium groups, along with some small groups and even individual isolated
plants, all widely scattered through the area. This land is privately owned and used for tree farming, as is much of the land in the Florida panhandle.
Most Threatened Population
The third known location is in Gulf County, Florida, and is again primarily on tree farming land and in even more widely scattered groups, These plants are found generally within a few miles of the Gulf Coast along sand ridges near wet situations, and some are close to populated areas. My sources in Florida stated that they had not visited the Gulf County habitat in a number of years and were unsure of the state of those plants. Despite the tiny population at Camp Blanding, my personal opinion is that the greatest risk of permanent loss of Chapman's rhododendron habitat is in Gulf County.
There is a difference of opinion as to whether Rhododendron chapmanii and its relatives,
R. carolinianum and R. minus, are separate species or merely varieties of
R. minus, and there exists some confusion and misinformation about differentiating between them. I will leave the species versus variety debate to the botanists, but from observing both wild and garden plants, I believe that the easiest and most reliable single method of identification is by bloom time.
R. chapmanii is the earliest, blooming for a two-week period around April 1st.
R. carohnianum, a mountain plant, begins its bloom as the pink blooms of
the Chapman's rhododendron are almost spent. R. minus, the most widespread and common of the three in the wild, blooms last, and there is no overlap at all with the flowering of
R. chapmanii and probably no natural hybrids between the two, as R. minus is not known
to exist in Florida.
Particular About Habitat
According to J. Patrick Tatum's excellent article in the Spring 1984
Journal ARS2, relating to the habitat of R. chapmanii, they are very particular about the constant water table of their habitat and grow only "on sands with abundant organic matter that are well drained at the surface, permanently saturated with 50ft,
acid water just below the surface, and yet never subject to flooding". I have never observed them growing very far from water, and this may partially explain their heat tolerance. It strikes me as ironic that a plant which is that particular about its native habitat survives these seemingly hostile activities of man and is easily grown in non-sandy soil much further north than its native Florida. The species
is available from the Rhododendron Species Foundation and numerous specialty nurseries. I believe that the known populations are stable at present, with no significant increase or decrease in numbers of plants in
1. Davidian, H. H. The Rhododendron Species, Volume 1, Lepidotes, Timber Press, 1982.
2. Tatum, J.. Patrick. "The Native Habitat of Chapman's Rhododendron," Journa ARS, Vol. 38, No. 2, Spring 1984. n