QBARS - v29n2 Species Rhododendrons Before 1850

Species Rhododendrons Before 1850
Discovery, Introduction, and Classification

Frank D. Mossman, MD, Vancouver, Washington

This paper is the first in a series on the history of rhododendrons. An attempt has been made to research the literature, which is not readily available, to give a resume of most of the species found before 1850.
The distribution of rhododendrons over the northern hemisphere has been ably and repeatedly described in recent literature. History of the various species is not so readily available. Who found them? What were their names? How did they come into domestic gardens?
The word rhododendron means rose tree. The Roman naturalist, Caius Plinius Secundus, Pliny the Elder, used the term rhododendron to describe what 'is now called Nerium oleander Rose-bay. Fifteen hundred years later a Frenchman, de L'Obel repeated Pliny's usage in 1576. In 1735, Karl von Linne (latinized Linnaeus), a Swedish naturalist, proposed the currently accepted binomial system of nomenclature to replace the cumbersome descriptive method that varied from one author to another, creating much confusion. Linnaeus used the term rhododendron in 1753 for only a few species: R. ponticum of Asia Minor, R. dauricum of Siberia, R. maximum from America, R. ferrugineum and R. hirsutum of the European Alps, and the circumpolar R. lapponicum . In Linnaeus' 'Supplement' R. chrysanthum was described. He listed Azalea as a separate genus, namely A. lutea (now R. canescens and R. calendulaceum ), A. nudiflora (now R. nudiflorum ), A. indica (now R. indicum ), and A. viscosa (now R. viscosum ). The names in parenthesis are the presently accepted equivalents of Linnaeus' names and show how taxonomists have changed the classification as their knowledge increased. Sometimes a species from more than one source received more than one name until the facts became apparent. The first properly published name with accurate description and figures became the accepted name. Occasionally, this meant the abandonment of well-established names. An example: R. californicum , Hooker, 1855 and R. macrophyllum , G. Don, before 1850, are now known to be the same species, therefore the name given by G. Don is the accepted name in the botanical world, and over one hundred years elapsed in elucidating this fact.
Some species have thrived in domestic gardens, others have disappeared because of cultural problems or lack of interest. Some species combined readily with others either naturally or with man's help so much so that the original species disappeared from domestic gardens. Through the years the 'wild' species became the parents of our modern garden hybrids by means of breeding programs, crossing one species with another species and so on. But many species are grown for their own sake, selected clones being much sought by the connoisseur of garden beauty.
The species very often grew in distant and very inaccessible places, and even when seen and appreciated by someone from the western world, it often remained for some later observer to collect plants or seed to be grown elsewhere. Sometimes, these natives grow in abundance nearby, and are only casually appreciated.
In the following table, the currently accepted species name is listed with the name of the taxonomist who described the species first and the year of that description. Very seldom was the discoverer, introducer, and describer one and the same.

Table of species, in chronological of introduction to Europe
R. hirsutum , Linnaeus, 1752 in Britain, 1656
R. viscosum , (John) Torrey, 1843
(swamp honeysuckle)
in England 1680 from John Banister in eastern North America to Henry Compton
R. indicum , (Robert) Sweet, 1833 in Europe 1680, to England 1833
R. viscosum , Torrey, 1843 in England, 1734, from John Bartram
R. nudiflorum , Torrey, 1824
in eastern North America to Peter Collinson
R. maximum , Linnaeus, 1752 in England 1736 via Peter Collinson
R. canescens , Sweet, 1830 in England by mid 18th century
R. ferrugineum , Linnaeus, 1752 in England 1752
R. canadense , Torrey, 1839 flowered in Paris in 1756, sent to England by Joseph Banks in 1767
R. ponticum , Linnaeus, 1752 in Britain circa 1763 from Gibraltar
R. chrysanthum , Linnaeus known in Russia 1769, introduced in England in 1796 by Joseph Busch
R. dauricum , Linnaeus, 1752 in Britain 1780
R. minus , Michaux, 1792
in England, 1786 via John Fraser from southeastern North America
R. speciosum , Sweet, 1830 collected by Francois Andre Michaux 1787
R. luteum , Sweet, 1830 sent by Peter Pallas to English nurserymen Thomas Bell, Lee & Kennedy in 1793
R. simsii , (Jules Emilie) Planchon, 1854 collected in China in 1793
R. camtschaticum , Pallas, 1784 known in 1784, introduced in 1799 to England
R. caucasicum , Pallas, 1784 in England 1803 by Peter Pallas
R. obtusum , Planchon, 1854 in England 1803
R. calendulaceum , Torrey, 1824
(flame azalea)
in Europe 1806 sent by Francois Andre Michaux; collected by William Bartram in 1774
R. catawbiense , Michaux, 1803 discovered and later introduced by John Fraser to England from North Carolina 1809
R. carolinianum , (Alfred) Rheder, 1912 to England c. 1810 via John Fraser
R. arboreum (James Edward) Smith 1805 to England 1810
R. arborescens , Torrey, 1824 in England c. 1818
R. mucronatum , (George) Don, 1834 in England, 1819 from Joseph Poole to Brookes Nursery at Ball's Pond
R. anthopogon , (David) Don 1821 in England 1821, sent by Dr. Nathaniel Wallich
R. molle , G. Don 1834 in England 1823, Loddiges nursery
R. campanulatum , G. Don, 1821 in England 1825, Dr. Wallich
R. setosum , D. Don in England 1825 to 1828
R. japonicum , Suringer, 1908 to Holland in 1830 by Philipp Franz von Siebold
R. reticulatum , D. Don 1834 to Holland 1832-3 by Joseph Knight of Chelsea
R. scabrum , G. Don, 1834 known in 1834 in Europe
R. albiflorum (Sir William Jackson), Hooker, 1834 known in 1834 in Europe
R. metternichii , Siebold and (Joseph Gerhard) Zuccarini, 1835 known in 1835 in Europe
R. obtusum , Planchon, 1854 in England 1844, sent by Robert Fortune from a Chinese garden
R. barbatum , Wallich to England by Dr. Wallich after 1849
R. formosanum , Hemsley, 1895 known to be in England in 1849
R. macrophyllum , G. Don, before 1850 known in England 1849
R. grande , Wight, 1847 and
R. griffithianum
, Wight, 1850
introduced to England by Mr. William Griffith in 1849
The given names in parentheses are omitted in scientific publications.
R. hirsutum and R. ferrugineum have long been known as the Alpen Rosen of the European Alps where they grow in profusion. R. hirsutum prefers a calcareous soil in its native environ whereas R. ferrugineum thrives on granite or slate soils. In 1914 Sir Herbert Maxwell described a large plant of R. hirsutum in Scotland three feet high with a twenty-one foot circumference. Both species do best in a moist climate. How the former came to be in England in 1656 before the other is not known.
R. ferrugineum R. viscosum
Fig.14. R. ferrugineum , the Alpen-Rosen
of the European Alps, was known in
England by 1752.
Drawing by Doris Mossman after illustr-
ation in "The Species of Rhododendron".
Fig.13. R. viscosum was sent to England
by John Bartram, who introduced many
ornamental American plants to the British.
Drawing by Doris Mossman

R. viscosum is a variable species closely related to R. serrulatum , R. arborescens , R. oblongifolium and R. atlanticum . These species are sometimes not easily distinguished from each other and have been frequently confused. An English missionary, John Banister in eastern North America, sent a drawing of R. viscosum to Dr. Henry Compton, Bishop of London; Leonard Plunkenet published it in 'Phytographia' in 1691. The actual introduction to England of the plant may not have occurred until about 1734 when John Bartram, an American farmer-horticulturist sent R. viscosum to Peter Collinson in England.
R. indicum , long a favorite of Japanese gardens, is native to Yakushima Island and possibly elsewhere in Japan. The name relates not at all to India, but rather to the fact that the Dutch took this azalea from Japan via Indonesia, called Indies by them, thence to Holland. Breyne's 'Prodromus' 1680, apparently made the first European mention of this plant. Mr. M'Killigan took the plant to England where it first bloomed at Knight's Nursery in 1834. There is much confusion about its part in the development of the 'Indian Azaleas'. Ernest H. Wilson believed that it had little or no part!
R. nudiflorum was discovered by John Banister, probably. Plunkenet described it as "Cistus virginiana Pericyclemeni flore ampliori et minus odorato." It was introduced to England between 1725 and 1730 by Peter Collinson who received it from John Bartram in America.
R. canescens was discovered by Mark Catesby, who published a picture of it in 1731. Michaux collected it in South Carolina between 1784 and 1796. It was probably introduced to England in mid-eighteenth century.
R. maximum was introduced to England in 1736 by Peter Collinson from eastern North America, but as such was never very popular there. The true species was reported to be at Leonardslea by J. G. Millais in 1917. This species was one of the chief progenitors of a hardy group of English garden hybrids.
R. canadense was first described and pictured by Henri Louis Duhamel du Monceau in the 'Botanic Garden' in Paris in March 1756, where it had been brought from Canada. Samuel Gottlieb Gmelin referred it to the genus Rhododendron in 1791, and that same year the species was introduced to England.
R. ponticum a native of Armenia, which country was known to the ancients as Pontus, was introduced about 1763 to England from Gibraltar, to which area and Portugal, probably, it had been introduced by man much earlier. Some regions of southern England are overrun by this species.
R. chrysanthum was founded by D. G. Messerschmidt in Russian Dahuria between 1720 and 1727. Peter Pallas brought it to Petrograd. Gmelin mentioned the species in 'Flowers of Siberia' in 1769. Joseph Busch introduced the species to England in 1796. In 1917 J. G. Millais reported that it was rare in English gardens because of shy blooming and health difficulties. The early hybridizers combined R. chrysanthum and R. caucasicum after 1803 with others to develop a valuable early blooming hardy group of rhododendron garden hybrids.
R. dauricum was also from Dahuria in Russia where the sub-alpine areas above the Lena and Yennesei are purple with the flowers of this species in May. It was described by Linnaeus in 1752 and was in England by 1780, where it blooms in January and February.
R. minus from southeastern North America, first described as such by Michaux in 1792, was long known as R. punctatum . John Fraser introduced the species to England in 1786 where it was still rare in 1917. R. minus was crossed with R. ferrugineum to give the curious shrub known as 'Daphnoides'.
R. speciosum was collected by Michaux on April 26 and 27, 1787 near Two Sisters Ferry on the Savannah River and described in his 'Flora' as A. calendulacea v. flammea . Several other early collections were also made of this species. Sweet assigned the present name in 1830.
R. luteum was found by Joseph Pitton de Tournefort on the east side of the Black Sea during 1700 to 1702 on his voyage to the Levant. In his 'Corallarium Institutionem' 1703, he described the species as "Chamae-rhododendron Pontica, maxima, mespili folio, flore luteo". This and two later accounts of the flower also made by him resulted in the Azalea Pontica description by Linnaeus. The species became popular in Britain and on the European continent. In Ghent it was combined with the eastern North American azaleas to develop the "Ghent Azaleas", of which many clones are still grown.
R. simsii has been much confused with R. indicum , R. scabrum , and R. obtusum partly because these species have been grown domestically in many places in the orient. R. simsii is native to China where it is especially abundant in the Yangtze Valley from near Ningpo west to Mt. Omei. It is also native to southern Formosa and the Kawanabe Islands, but not found native in Japan or Korea. It is twiggy and much-branched, to three meters high, with a profusion of red flowers. The so-called 'Indian Azaleas' of western gardens were originated almost entirely from this species since about 1850 in Belgium, France and Germany.
R. camtschaticum a native of N.E. Asia to Japan, coastal Alaska and British Columbia also abundant in West Greenland was first introduced to Britain in 1799. It was rare in British gardens in 1917 due to problems of cultivation.
R. caucasicum was also found by Toumefort. It was sent to England by Peter Pallas in 1803, and was much used by early hybridizers to develop a hardy group of garden shrubs.
R. calendulaceum , described as Azalea lutea by Linnaeus in 1753, and changed by him to A. nudiflora in 1762, was discovered in northern Georgia in 1774 by William Bartram who described the species as Azalea flammea in 'Travels' (1790). There were numerous introductions from America to Europe where the species was highly prized.
R. catawbiense , was introduced to Britain by John Fraser in 1809 from southeastern United States. Through selection and hybridization this species was parent to a very valuable group of May flowering garden rhododendrons, including 'Everestianum' and 'Fastuosum'.
R. carolinianum , was imported to England by John Fraser of Sloane Square in 1810, where it was hardy but the original stock was apparently lost.
R. arboreum , was introduced to England about 1810. This species was found by Captain T. Hardwick in the Sewalic chain of the Himalaya while on tour to Sireenagur. It was published in 1805 in the "Exotic Botany" by Sir James Edward Smith who described the very rich scarlet flowers and leaves with silvery undersides. Major Madden mentioned it on the mountains of Kamaoon at elevations of 3,500 to 10,000 feet up to forty feet in height. At Nynee Tal a trunk of sixteen feet circumference was observed. Exactly who first introduced this splendid species to England is not recorded, but Dr. Wallich sent it again about 1827. This tender species was used in hybridizing to produce red flowers.
R. arborescens was probably discovered by John or William Bartram, and appeared in Bartram's catalogue as Azalea arborea . It may have been sent to England by the Bartrams before the introduction date of 1818 stated by Robert Sweet. Pursh referred to it as the finest ornamental shrub he knew in 1814 after seeing it in the Bartram garden. Ernest Henry Wilson stated this handsome plant was still very seldom seen in cultivation in 1921.
R. mucronatum , variously described as Azalea rosmarinifolia, (Johannes) Burman (1768); Azalea mucronata, (Carl Ludwig) Blume (1823); Azalea indica alba, Lindley (1824); Azalea ledifolia, Hooker (1829) and other names familiar to gardeners, was mentioned by Engelbert Kaempfer in 1712 under its Japanese name "Jedogawa-tsutsuji". According to John Lindley in 1824, this species was sent to Joseph Poole from China to Brookes Nursery at Ball's Pond in 1819. This plant is very common in Japanese gardens, especially from Tokyo southward. Several color forms have been described. The native of Japan is lilac purple on Shikoku. For long, it was thought to be a greenhouse variety but is now grown outside in some areas of the occident.
R. anthopogon a native of the high Himalaya up to 16,000 feet elevation from Cashmere eastward was found at Gossain Than by Dr. Nathaniel Wallich who introduced it to England.
R. molle , is abundant in eastern China, from which it has been introduced several times, the first being in 1823 through the Nursery of Loddiges who figured it in "Botanical Cabinet" (1824) as Azalea sinensis . It closely resembles R. japonicum with which it has been hybridized to form the popular group of "Mollis Azaleas".
R. campanulatum was found by Dr. Wallich who sent seed to England in 1825 from the Himalayas to Britain where the species is popular because of hardiness, free-flowering, and shapely truss. In some areas of England the species seeds itself nearly as freely as R. ponticum . There is considerable variation in leaf and flower.
R. setosum , a Himalayan alpine was introduced to England between 1825 and 1828, but apparently succeeded well only in Scotland.
R. japonicum , was known by other names and often confused with the Chinese deciduous azalea species R. molle . It is native only to Japan where it is common over a great part of Hondo, the main island and elsewhere. Taken to Holland in 1830 by Philipp Franz von Siebold, it was used in hybridizing with R. molle to produce the "Mollis Azaleas".
R. reticulatum , a native of much of Japan, was brought to England by Knight of Chelsea about 1832 to 1833, but it may have been lost. Several later introductions were made.
R. scabrum , is endemic to the Okinawa group of Liukiu Islands and is cultivated in Japan. Occidental introduction was not till 1864 in Petrograd.
R. albiflorum , was discovered by Mr. Drummond during the early nineteenth century. Seeds were sent to Dr. Graham of Edinburgh, where it flowered in Scotland in 1837. John G. Millais reported having seen thousands of acres of it growing above 4000 feet elevation in the mountains of Washington State and British Columbia in such dense thickets as to be called 'The Miner's Curse'.
R. metternichii was first described by von Siebold in 'Flowers of Japan' in the early part of the nineteenth century but apparently was not introduced to Europe until somewhat later.
R. lepidotum , first described as such and introduced to England by Dr. Wallich from the Himalayas where it grows up to 16,000 feet elevation, is hardy at Kew.
R. obtusum , known as a garden plant for centuries by the Japanese who called the shrub "Kirishima-tsutsuji", was mentioned in 1712 by Kaempfer, who used the Japanese name. It is a native of Japan, but was introduced to England in 1814 by Robert Fortune from a Chinese garden. The 'wild' form, called R. obtusum f. japonicum E. H. Wilson was considered by him to be the parent of all "Kurume Azaleas". This species was described as Azalea indica Carl Peter Thunberg in 'Flowers of Japan' in 1784.
R. formosum , found by Smith in 1815 on the mountains bordering Silhet in the eastern Himalayas, apparently was not known in English gardens until 1849 when it became popular as a greenhouse plant. Crossed with R. edgeworthii , it produced the well known hybrid 'Fragrantissimum'.
To R. macrophyllum , Sir William Jackson Hooker refers as editor in his preface for 'Rhododendrons of Sikkim Himalaya', 1849. William Lobb is credited with having introduced to England this species and R. occidentale , (Asa) Gray in 1850. This same collector for Veitch and Sons of Exeter also was responsible for the introduction of R. javanicum from the mountains of Java, where he noted that several species were epiphytal.
R. grande and R. griffithianum were found by Mr. William Griffith during his travels in Bootan (Hooker's spelling) and published in Dr. Robert Wight's 'Icones' in mid-nineteenth century.
Drs. Horsfield, Carl Ludwig Blume and William Jack described rhododendrons from the Java mountains, 1822 to 1838: R. javanicum , R. album , R. retusum , R. tubiflorum , R. malayanum , and R. celebicum . Blume was first to note an epiphytal rhododendron, R. (vireya ) album . Mr. Low described numerous rhododendrons in Borneo, several epiphytes.
Thus the world's explorers were often followed by men who saw, described and sometimes collected plant material for use in their homelands. The next article by this writer will describe the efforts of Sir Joseph Dalton Hooker, a major collector of rhododendron species.


1. The Rhododendrons of Sikkim-Himalaya by Joseph Dalton Hooker, 1849
2. Rhododendrons. by John G. Millais, 1917
3. Trees and shrubs Hardy in the British Isles, by W. J. Bean, 1921
4. Monograph of Azaleas by Ernest Henry Wilson and Alfred Rehder, 1921
5. The Species of Rhododendron, editor J. B. Stevenson, 1930
6. Azaleas, by Frederick Street, 1951