A History of Rhododendrons
Lamellen, Cornwall, England
Rhododendrons are one of the main features of Cornish gardens, due to Cornwall's relatively mild climate and early spring. Though perhaps past their best by May, they have the advantage of a wide range and a long flowering season, so a display can still be put on after the other mainstays of the County Flower Show, camellias, daffodils and magnolias are over.
The name "rhododendron" derives from the Greek rhodo, rose, and dendron, tree. The genus belongs to the heather family, Ericaceae. The earliest record of rhododendrons comes from the disaster which befell the army of Xenophon, retreating from Babylon in 401 B.C., which camped in the Armenian hills inland from Trebizond on the Black Sea coast of Turkey. The starving soldiers consumed large quantities of honey made from the poisonous nectar of the yellow flowered Pontic Azalea, Rhododendron luteum, and were overcome by nausea and vomiting. A similar disaster affected the army of Pompey in the same area in his campaign against King Mithridates of Pontus in 66 B.C. and also the army of Alexander the Great of Macedonia on his way to India in 327 B.C., although this was not in the same area and was probably due to R. afghanicum.
Rhododendron is primarily a Northern Hemisphere genus, extending from North America across Europe and Asia to Japan, and from the extreme north to the Equator. One mainly tropical section grows also south of the Equator in New Guinea, with a single species in Queensland, Australia. Rhododendrons do not occur in the wild anywhere in Africa, or in Central or South America, though there is a considerable colony in one area in Jamaica, which is probably of garden origin.
The first record of a rhododendron in cultivation in Britain is of R. hirsutum from the central and eastern Alps cultivated by John Tradescant in 1650. The allied Alpenrose, R. ferrugineum from the western Alps and Pyrenees, was in cultivation in Britain in 1740. These are both slow growing evergreen shrubs of three feet or so.
The rampant R. ponticum, primarily from the Pontus Mountains and the Black Sea region, is also a native of Portugal and southern Spain. It was first introduced into Britain from Gibraltar in 1763, and only later from the Black Sea region. This is the rhododendron which seems to have been allowed to get out of control in the Snowdonia National Park and has been causing much ill-informed concern to the "Greens" and to the media.
From Siberia came R. dauricum in 1780 and R. chrysanthum in 1796. Rhododendron luteum was introduced from the Caucasus in 1792 and R. caucasicum in 1803. Rhododendron camtschaticum came from Kamtschatka in 1799 and grows on both sides of the Bering Straits.
Introductions from North America were only a little later in time. In 1680, the Bishop of London was sent a plant of the swamp honeysuckle, the azalea, R. viscosum by a missionary in Virginia. Other early introductions of deciduous azaleas were R. calendulaceum in 1730 and R. canescens in 1739. The first evergreen rhododendron species from America, R. maximum was introduced two years after that, R. minus in 1976 and R. catawbiense in 1809. From Canada came the azalea R. canadense in 1767 and in 1825 the dwarf R. lapponicum, which also grows in Alaska, Siberia, Greenland and of course, Lapland.
The first introduction from India was R. arboreum, first reported from the western Himalayas in 1796, but there is no authentic record of its introduction before 1817. Rhododendron campanulatum from Nepal followed in 1825, R. barbatum in 1829 and R. formosum from Assam in 1843.
The deciduous azalea, R. molle, was introduced from China in 1823. Robert Fortune, who had been sent out by the Horticultural Society to introduce the tea plant, Camellia sinensis, brought back seed in 1855 from eastern China (Chekiang province) of a rhododendron which Lindley named R. fortunei.
Of the mainly tropical Malesian (Vireya) species, R. brookeanum (named after Sir James Brooke, the Rajah of Sarawak) was sent from Borneo in 1845. The following year, Thomas Lobb, a Cornishman working for James Veitch of Exeter, sent R. javanicum and R. jasminiflorum from Java and Sumatra respectively. Later, he also introduced from the Malayan Peninsula and lower Burma R. malayanum, R. moulmainense, and R. veitchianum. Over the years, the Veitches were instrumental in sending collectors all over the world and introducing a great many valuable plants into cultivation in Britain, but no more rhododendrons until they sent E.H. Wilson to China in 1899.
The Hooker Family
Meanwhile, the impetus for the introduction of rhododendrons passed to the Hooker family, also of Exeter origin. In 1820, at the age of thirty-five, on the recommendation of Sir Joseph Banks, William Jackson Hooker was appointed Professor of Botany at Glasgow University, where he remained until 1841. He was largely responsible for the development of the Botanical Garden there. William Hooker, was knighted in 1836 and five years later was appointed Director of Kew.
In 1839, his eldest son, Dr. Joseph Dalton Hooker, by then aged twenty-two, sailed in H.M.5. Erebus as assistant surgeon and botanist with Captain Ross' Antarctic expedition. The Ross expedition returned in September 1843.
Joseph Hooker, while continuing to be a naval officer, worked at Kew for the next five years after which, through the patronage of the First Lord of the Admiralty, Lord Auckland, he left for India travelling in the same ship as the new Governor General, Lord Dalhousie. His Kew friend, Hugh Falconer, travelled out in the same party, on his way to take charge of the Saharanpur Botanic Garden. Later Joseph Hooker named three rhododendron species which he collected after these gentlemen: Rhododendron aucklandii (now known as R. griffithianum), R. dalhousiae (after Lady Dalhousie) and R. falconeri.
From Calcutta, Joseph Hooker travelled north to Sikkim and spent two years there exploring in the hills, based in Darjeeling where his host was Brian Hodgson, the British Resident in Nepal. Another friend was Dr. Archibald Campbell, the Superintendent of Darjeeling and Political Agent, Sikkim. Their help to him is recalled in the naming of Rhododendron hodgsonii, Magnolia campbellii and Rhododendron campbelliae (the latter after Mrs. Campbell).
Dr. Thomas Thomson, an old college friend from Glasgow days, was then employed by the East India Company, and he accompanied Hooker on tours in the Khasia Hills, in Assam and in East Bengal. He is commemorated by R. thomsonii. Thomson collaborated with Joseph Hooker in the production of a Flora Indica. He later succeeded Dr. Wallich as Superintendent of the Calcutta Botanic Garden, about the same time as Joseph Hooker succeeded his father as Director of Kew.
Wallich had sent seed of R. arboreum and introduced R. campanulatum from Nepal in 1825. The closely related R. wallichii was named after him by Hooker.
Joseph Hooker's expedition is immortalized in his Rhododendrons of the Sikkim Himalaya published in three parts between 1849 and 1851, with thirty coloured plates, edited by Hooker's father. Before 1848, only thirty-three species of rhododendron were in cultivation; Hooker collected, sketched and described forty-three species of which thirty-six are still recognised as distinct.
Seed from his collections was grown on at Kew and seedlings were sent to friends in the west of Scotland, Wales and southwest England to try out, notably to the Shilson family at Tremough near Penryn, to Robert Were Fox at Penjerrick and to Sir Charles Lemon at Carclew. These formed the basis for the good quality hybrids that were made in Cornwall in the latter part of the 19th century, such as 'Shilsonii', 'Beauty of Tremough', 'Penjerrick', 'Barclayi' and 'Cornish Cross'. 'Sir Charles Lemon' is usually regarded as a natural hybrid of R. arboreum and R. campanulatum.
The French Missionaries
Meanwhile the rhododendrons of western China, Tibet and upper Burma began to be discovered. Robert Fortune's introduction from eastern China (Chekiang), R. fortunei, extends as far west as eastern Szechuan. But no rhododendrons had been reported from further west than this until the journeys of Pere Armand David, a very fine naturalist of the Missions Etrangeres, between 1869 and 1874. From Chungking on the Yangtse river, he travelled to Chengtu, the capital of Szechuan, and then to Mupin on the Tibetan border. It was here that he found Rhododendron davidii, R. decorum, R. moupinense and R. strigillosum, as well as Davidia involucrata and other plants of first class garden importance.
Pere Jean Marie Delavay of the same mission was initially stationed in Canton province where in 1867 he collected for the British Consul, H.F. Hance, after whom R. hanceanum is named. Later he lived for ten years in the hills between Talifu (now Kunming) and Lichiang, one of the richest areas of vegetation in northwest Yunnan. Here he found Rhododendron ciliicalyx, R. fastigiatum, R. irroratum, R. racemosum, and R. yunnanense, as well as such valuable plants as Magnolia delavayi, Meconopsis betonicifolia and Osmanthus delavayi.
Between 1892 and 1903, Pere Paul Farges collected in northeast Szechuan, where he found Rhododendron discolor, R. fargesii and R. sutchuenense among other plants. While Pere Jean Soulie, collecting in north Yunnan and eastern Tibet between 1886 and 1905 found, among other fine plants, Rhododendron ramosissimum and R. souliei. In the same area in 1891, R. yanthinum was found by Prince Henri d'Orleans, who on a later expedition was the first European traveler to explore the great hills and valleys in the extreme north of Burma. This is the area that was so thoroughly worked over later by Farrer, Kingdon Ward and Forrest.
The French missionaries for the most part did not collect seed, but sent plants to Paris to the Ecole de Botanique and herbarium specimens to the Museum of Natural History, where many of them were described and named by Adrien Franchet. Sadly, a considerable number of Delavay's specimens remained unexamined.
Meanwhile, an Irishman, Augustine Henry, was posted in 1861 as Medical Officer and Assistant with the Imperial Chinese Customs Service at Ichang in Hupei province on the Yangtse river, 1,000 miles from the sea and the inland terminus for the river steamers from Hankow. Here he remained for the next eight years, but he spent his weekends collecting in the gorges a few miles to the north and he sent specimens to Kew. These included both some of the species collected by the French missionaries and others that were new, notably the late flowering R. auriculatum. Rhododendron augustinii was named after him at Kew.
Henry retired from the Chinese Customs at the end of 1900 and on his return to the United Kingdom he took up forestry. After a course at the French School of Forestry at Nancy, he worked with H.J. Elwes on the production of the seven volumes of The Trees of Great Britain and Ireland and he started the School of Forestry at Cambridge. He was partly instrumental also in the formation of the Forestry Commission and in 1913 he was appointed Professor of Forestry at the College of Science in Dublin where he remained until 1926.
The Veitches' Role
Up to now, the valuable exploration that was being done in western China was carried out by people who were not primarily botanists, and had other professions, plant hunting being a leisure hobby. Delavay and Henry sent back a certain amount of seed, but the first serious attempt to collect seed of the plants endemic to western China was due to the initiative again of Messrs. Veitch. By this time, both the Arnold Arboretum at Harvard University in Massachusetts and the Royal Botanical Garden at Kew were expressing interest in introducing some of the fine plants that the French missionaries, Augustine Henry and other travelers had found in western China.
In 1899 therefore, James Veitch sent out Ernest Henry Wilson, a Kew student recommended by Sir William Thistleton-Dyer, who had succeeded his father-in-law, Sir Joseph Hooker as Director. After six months spent at Veitch's Coombe Wood Nursery, Wilson sailed for China in April 1899, by way of the United States. There he visited Arnold Arboretum to make the acquaintance of Professor C.S. Sargent.
Wilson crossed the Pacific, reaching Hong Kong on June 3rd and from there travelled inland to Szemao in southwest Yunnan, where he spent a month or two with Augustine Henry. On the latter's advice, he went north to the west of Hupah province. Working from Ichang, he brought back seed of many of the plants Henry had found there including Davidia involucrata and sixteen rhododendron species under twenty-three seed numbers. This was between 1899 and 1902.
His second expedition for Messrs. Veitch was more fruitful. This time he went to west Szechuan where he worked from Kiating-fu on the Min river and made several expeditions both west to the Tibetan frontier and north to the Kansu border. Between these he explored the holy Mount Omei, one of the triangle of mountains west of Kiating-fu enclosing the Laolin or "wilderness of very wild country."
On this expedition, he collected seed of thirty-six species of rhododendron under fifty-five seed numbers. These included several that had been found by Peres David and Soulie and a notable new discovery on Mount Omei, R. calophytum. He also found R. davidsonianum which he named after the doctor at the Friends Mission, who saved his leg, badly broken in an avalanche on a later expedition. Another discovery was Wilson #1539, R. magorianum, of which the herbarium specimen is a Cocculus.
It is the experience in Great Britain that rhododendrons require an acid soil and will not thrive on one that is alkaline. It is of interest therefore that most of the Laolin and these three mountains are on hard limestone, as were the gorges north of Ichang in northwest Hupeh where Henry worked. East of Tali, Forrest later found a number of species on the same subsoil and a number of species in the wild appear to grow on magnesium limestone. It is apparently calcareous limestone which does not suit them. Among other species which Wilson found on Mount Omei and Washan on this subsoil were Rhododendron argyrophyllum, R. concinnum, R. insigne, R. strigillosum and R. williamsianum, as well as Magnolia sargentiana.
Wilson was later invited by Professor Sargent to visit China again on behalf of the Arnold Arboretum. For them he collected in west Hupeh and west Szechuan between 1906 and 1909 and again in 1910-11, when he recorded respectively ninety-two and fifty-four seed numbers, including some new species and notably the good blue form of R. augustinii, Wilson #4238.
A few years older than Wilson, George Forrest started collecting in China a few years later. A Scotsman, he worked in the herbarium of the Royal Botanic Garden at Edinburgh, and was selected by the Regius Keeper, Sir Issac Bayley Balfour, to explore and collect in the area further west than Wilson had been.
His first expedition, to Yunnan and southeast Tibet, was to collect for A.K. Bulley of Bees Ltd. at Neston in Cheshire, to whom all his seed was sent. He collected rhododendron seed under ninety-five seed numbers between 1904 and 1906.
Six subsequent expeditions over the next twenty-five years were organised by the Royal Botanic Garden at Edinburgh, and paid for by syndicates, of whom the leading member was J.C. Williams of Caerhays. Forrest entered the area through upper Burma, travelling by Bhamo to Tengyueh and Myitkyina. He explored the botanically rich country through which four of the great rivers of eastern Asia flow north to south in an area less than one hundred miles wide, the Nmai Hka (the eastern branch of the Irrawaddy), the Salween, the Mekong and the Yangtse. He trained native collectors, mostly Mosso tribesmen from a village in the Lichiang range in northwest Yunnan, who covered a wide area and found and collected seed of many new species.
A slightly younger man was Reginald Farrer, author of The English Rock Garden. He had made a fine garden on the limestone hills at Ingleborough in Yorkshire and collected in the European Alps, on one of which expeditions my father accompanied him.
From what he had read about the travels of the Russian explorers, Przewalski and Potanin in the 1870's and 1880's, Farrer decided to visit Kansu province, to the north of Szechuan and bordering Tibet. This he did in 1914, inviting my father to accompany him, but father by then had got married. In later times, father frequently said how much he regretted the missed opportunity.
Instead, Farrer took William Purdom, who had already travelled for Veitch and the Arnold Arboretum in the Tsinling range. Later Purdom became Inspector of Forests to the Chinese Government. Rhododendron purdomii was named after him at the Arnold Arboretum. Because of the war, few of Farrer's plants from this expedition have survived in cultivation.
He returned in 1919, this time to upper Burma and was accompanied for the first season by Euan (E.H.M.) Cox. The following year he was more successful and collected seed of thirty-seven rhododendron species under forty-two seed numbers, including the tender Rhododendron megacalyx and R. crassum and the large leaved R. sinogrande, R. arizelum, R. basilicum, and R. sidereum. Forrest was collecting in much the same area about the same time. They both collected the interesting R. mallotum, at first named by Balfour aemulorum (the rivals). Farrer died in the field on October 17th, 1920.
Kingdon Ward's Explorations
Next came Frank Kingdon Ward, son of the professor of Botany at Cambridge, and with a Cambridge degree in Natural Science. A.K. Bulley of Bees Ltd. engaged him in 1911 to undertake an expedition in northwest Yunnan. Over the next forty-five years, apart from the two World Wars, he made a succession of expeditions in upper Burma and western China, extending into southeast Tibet, Sikkim, Bhutan and Assam. During this time, he found and introduced many new rhododendron species, as well as collected seed of most of the species discovered by those which had gone before. He thoroughly explored the parallel valleys of the four great rivers and wrote several books about his travels.
Another important collector working in western China for the USA was Joseph Rock. Born in Vienna in 1879, he was a trained botanist and had an extraordinary aptitude for languages. Between 1923 and 1933 he covered most of the ground already worked by Wilson, Farrer and Forrest in Yunnan, southeast Tibet and Kansu and collected many species, but few that were not known already. He visited the area again in 1948-49.
Between 1934 and 1938, and again in1946-9, Ludlow and Sherriff collected in Bhutan and southeast Tibet. In more recent years, a number of other people have also collected in this general area.
Introductions from Japan, Korea and Taiwan
We have Wilson to thank for the first introductions of rhododendrons from Japan, Korea and Taiwan, from expeditions which he made for the Arnold Arboretum in 1914-15 and 1917-19. He introduced a number of deciduous azalea species and also Rhododendron pseudochrysanthum and R. morii.
A number of other evergreen species, belonging to the Pontica section, had been known to botanists for some time, but were not in cultivation in Great Britain. Of these, the most important are the R. degronianum alliance. The finest of these is R. yakushimanum, first described by a Japanese botanist in 1920. It was introduced into Great Britain in 1934 when two plants were sent by Koichiro Wada to Exbury, who passed one on to Wisley.
European and North American Species
The European and North American species began to be planted to a limited extent in British gardens early in the 19th century. Several nurserymen, mostly near London, began to distribute them, notably the Waterers at Knaphill and Bagshot and the Veitches at Exeter. Rather earlier introductions had been made by Loddiges at Hackney, Lee and Kennedy at Hammersmith, Thompson at Mile End, Russell at Battersea and Standish and Noble at Sunningdale.
Early British Hybrids
The first hybrid recorded was an azaleodendron, a chance hybrid between R. calendulaceum and R. ponticum which occurred in Thompson's Mile End Nursery. By1819 there was a plant of this in the collection at the Royal Botanic Garden at Edinburgh, listed as R. subdeciduum 'Thompson's Hybrid'.
Purposeful breeding began with the crossing of the evergreen North American species R. maximum and R. catawbiense with the European R. caucasicum and R. ponticum, and a little later with R. arboreum from the Himalayas.
One of the earliest hybridisers was the Reverend William Herbert, Rector of Spofforth in Yorkshire and later Dean of Manchester, who produced a number of azaleodendrons as well as evergreen hybrids.
This inspired his elder brother, the Earl of Carnarvon, to institute extensive experiments at Highclere Castle in Berkshire under the supervision of J.R. Cowen, who later became Secretary of the Royal Horticultural Society. They produced 'Altaclerense', a hybrid between R. arboreum and a R. catawbiense/R. ponticum cross. There is an original plant of this at Tregothnan, but the massive 'Cornish Early Red' of Cornish gardens which it resembles, seems to be mainly 'Smithii' (R. arboreum x R. ponticum). 'Smithii' was made by William Smith, gardener to the Earl of Liverpool at Coombe Wood, Kingston on Thames, which later became the Veitch nursery that distributed the early Chinese introductions.
This cross was also made at Randall's nursery at St. Augstell. This is likely to be the source of most of the plants of this hybrid in Cornwall. The International Rhododendron Register treats the 'Cornish Early Red' as a synonym of 'Russellianum' (R. arboreum x R. catawbiense), made at Russell's nursery at Battersea, but this form seems to be less common in Cornwall. The big plants of the 'Cornish Early Red' in the garden of the Emperor's Summer Palace at Petropolios, forty miles north of Rio de Janeiro, Brazil, are likely to have been presents sent by Veitch with William Lobb on his first visit to South America in 1840.
Dean Herbert also produced the low growing early flowering hybrid 'Jacksonii' (Venustum) by crossing R. arboreum with R. caucasicum in 1833. The reverse cross, made by the elder Anthony Waterer at Knaphill the previous year produced the well-known 'Nobleanum' which flowers at Christmas.
The "Hardy Hybrids"
This marked the era of the hardy hybrids, a race of nursery-bred rhododendrons, mostly many generations removed from the wild species, which are very hardy, flower mostly in late May or early June, tolerate exposure and full sun and have firm upright many flowered trusses in a wide range of coloring from white to deep red. By the early 1850's, many such hybrids were being offered by Standish & Noble at Sunningdale and the Waterer firms at Bagshot and Knaphill. Most of these, unfortunately, were grafted on R. ponticum stocks. This was before it was realized what a very vigorous species this is, and in all too many cases the stocks overwhelmed the scions. This accounts for the clumps of R. ponticum in many old gardens, where originally more attractive hardy hybrids had been planted.
By 1900, the development of the old style hardy hybrids had more or less run its course. Hybrids started to appear with Rhododendron griffithianum, R. thomsonii or R. fortunei in their parentage, notably 'Pink Pearl' from J. Waterer in 1897. Volume I of J.G. Millais' Rhododendrons in 1917 listed 484 hardy hybrids raised in Europe and at that time available, of which 292 originated with the Waterer firms at Bagshot and Knaphill.
The cultivation of the choicer types of rhododendrons really dates from Joseph Hooker's travels in Sikkim, when seedlings raised at Kew were sent for trial to some favoured gardens. At Tremough, Richard Gill, the Shilson family's gardener, produced 'Shilsonii' (R. barbatum x R. thomsonii) A.M. 1900, 'Duke of Cornwall' (R. arboreum x R. barbatum) A.M. 1907 and 'Ernest Gill' (R. arboreum x R. fortunei) A.M. 1918. His finest hybrid however has been 'Beauty of Tremough' (R. griffithianum x blood-red R. arboreum) made in 1893, which was awarded an F.C.C. at the Truro Show in 1902. Seedlings of this cross were sent to other gardens in Cornwall and to Sir Edmund Loder at Leonardslee in Sussex. These plants ranged in colour from the white with a slight pink flush of 'Trebianum' to 'Gill's Triumph' with large crimson-scarlet flowers. They have received one F.C.C. and five A.M.s, one from Bodnant as recently as 1981 as 'Treetops'. The cross had actually been made previously at Haligan, and named 'John Tremayne' and 'Mrs. Babington', at Tregrehan as 'Carlyon's Hybrid' and at Scorrier as 'Scorrier Pink'.
At Penjerrick, Robert Were Fox's gardener, Samuel Smith, also produced a number of good hybrids, including 'Penjerrick' (R. campylocarpum x R. griffithianum) and 'Cornish Cross' (R. griffithianum x R. thomsonii), as well as 'Werei' of the same parentage as Gill's 'Duke of Cornwall'.
Outside Cornwall, James Mangles (1832-84) at Valewood near Haslemere in Surrey, who became known as "the High Priest of the Rhododendron Cult" raised some very good hybrids, using R. griffithianum in particular as a parent. On his premature death, his seedlings passed to his brother and sister at Littleworth near Farnham, but just before his death he sent several of his R. griffithianum hybrids to his friend, F.D. Godman, at South Lodge near Horsham. He grew them on in a cold greenhouse and one proved to be of remarkable beauty. When it grew too large for the greenhouse, branches were cut off, from which Sir Edmund Loder, across the road at Leonardslee, made numerous grafts. These were widely distributed as 'Loder's White', a very fine white hybrid.
On James Mangles' death, his mantle rather fell on Sir Edmund Loder (1849-1920), who crossed R. griffithianum with almost every rhododendron likely to produce good results, in the process, he produced many good hybrids, including the superb 'Loderi' group of which the seed parent was a good form of R. fortunei at Leonardslee and the pollen parent a particularly good form of R. griffithianum in the greenhouse at South Lodge. This cross first flowered in 1907.
The cross had originally been made at Kew as far back as 1875 and registered in 1888 as 'Kewense', but this cross does not compare with the 'Loderi'cross in quality. Even earlier, Luscombe at Coombe Royal near Kingsbridge in south Devon had crossed R. fortunei with R. thomsonii to produce 'Luscombei' in 1880, still a very good hybrid. 'Pride of Leonardslee' is perhaps the best of this cross.
A New Era for Rhododendrons
With the advent of rhododendron seed from western China, Tibet, upper Burma and Assam at the beginning of this century, a new era for rhododendrons opened. Some seed came from expeditions organized by Messrs. Veitch, who later distributed seedlings from their Coombe Wood nursery.
J.C. Williams of Caerhays Castle, Lord Lieutenant of Cornwall and grandfather of the present owner, F. Julian Williams, distributed seed from Wilson's expeditions when he started to work for the Arnold Arboretum. He also backed George Forrest's 1910 and 1912-14 expeditions and distributed seed from them. Williams named many of his hybrids after birds and butterflies: 'Blue Tit', 'Yellow Hammer', 'Red Admiral' and so on.
Inspired by J.C. Williams, the owners of other gardens in Cornwall started growing and hybridising rhododendrons, notably his cousin P.D. Williams at Lanarth, and my father E.J.P. Magor at Lamellen. My father had begun hybridising in 1912 and kept close touch with J.C. Williams and with Professor (later Sir lssac) Bayley Balfour, the Regius Professor at Edinburgh, who advised him on a method of naming interspecific hybrids which would record their parentage.
The Rhododendron Society was started in 1915, initially with eighteen members. Early numbers of the Society's annual notes contain records of these new Chinese species being grown in Cornwall and by 1920 records began to appear of the flowering of their crosses with Himalayan species. 'Oreocinn' (R. oreotrephes x R. cinnabarinum) and 'Ambkeys' (R. ambiguum x R. keysii) from Lamellen were the first to be recorded this way.
After the war, Major G.H. Johnstone at Trewithen and Colonel (later Sir) Edward Bolithe at Trengwainton also started planting and hybridising rhododendrons. In 1920, notes began to appear from Major Lionel de Rothschild M.P., who had bought Exbury in 1918 and had been elected to the Rhododendron Society two years later. The Hon. H.D. McLaren, son of the First Lord Aberconway was elected to the Society in 1923. He had started to plant rhododendrons in his mother's garden at Bodnant in 1909 and in the 1924 and 1925 Rhododendron Society Notes, he contributed a very good article on how some of Wilson's Chinese species were thriving there.
Lionel de Rothschild and Henry McLaren each paid regular visits to Cornwall every spring for a number of years, as did Colonel Stephenson Clarke from Borde Hill and later J.B. Stevenson from Tower Court. All four bought freely for their gardens any young hybrids available, in many cases new un-flowered hybrids. Rather earlier the Loder brothers had done the same, Sir Edmund from Leonardslee and Gerald (afterwards Lord Wakehurst) from Wakehurst. In this way crosses initiated in Cornwall were later registered and exhibited from other gardens where they had been raised.
Other visitors to Cornwall, not quite so frequent, were Sir Frederick Moore and Armytage Moore and Lord Headfort from Ireland and Lord Stair from Scotland. In this way Cornish rhododendron hybrids have spread all over the British Isles.
Shortly before the Second World War, Lieutenant Colonel (later Major General) Eric Harrison bought Tremeer in north Cornwall and started to plant rhododendrons, mainly obtained from over the hill at Lamellen. J.C. Williams had made the dwarf hybrid 'Blue Tit' (R. augustinii x R. impeditum) in 1933. My father had liked it so much that he made the reverse cross and planted a hedge at Lamellen. When General Harrison returned to Tremeer after the war, the hedge was not thriving. With my mother's permission, he took many cuttings from it, from which he raised 'St. Beward' and 'St. Tudy', both of which have since been awarded the F.C.C. after trial at Wisley.
Over the next twenty years, General Harrison did a lot of hybridising at Tremeer, concentrating on producing in particular blue dwarfs and yellows, mainly of the 'Comely' grex (R. concatenans x 'Lady Chamberlain'), but also using the Logan form of the Lamellen hybrid 'Damans' (R. campylocarpum x 'Dr. Stocker'). He made some good hybrids crossing R. williamsianum with 'Barclayi' from a layer obtained from Lamellen.
In 1961 he married Roza, widow of J.B. Stevenson of Tower Court, whose species collection was bought for the nation and is in Windsor Great Park. She brought with her to Tremeer a number of fine hybrids made by her husband and later herself, as well as the collection of Kurume azaleas selected for Stevenson by Koichiro Wada, as all being better than the "Wilson Fifty."
Apart from General Harrison, a number of fine hybrids have been made in the last twenty years at Windsor, Bodnant and Exbury.
At Glendoick in Perthshire, the nursery started by E.H.M. Cox after the First World War, some good dwarf hybrids have been made, mostly named after game birds. This nursery has also done a useful service in bringing over from America one or two of the species introduced by Rock which never reached Great Britain, notably R. hemsleyanum.
Some good hybrids have been made using R. yakushimanum as a seed parent, though it is doubtful whether any are as good as the best form of R. yakushimanum itself. Percy Wiseman, working at Waterer's Sunningdale nursery and using pollen from such hardy hybrids as 'Britannia' and 'Doncaster' has produced what may be a race of miniature hardy hybrids suitable for small gardens. Some of them are named after Snow White's Seven Dwarfs. 'Grumpy', 'Happy', 'Sleepy' and 'Sneezy' have been awarded the F.C.C. after trial at Wisley, as have several rather better quality hybrids, notably 'Dopey' and 'Percy Wiseman' and one or two others made at Windsor and by Arthur George at the Hydon Nursery.
Since the war, several people have collected in Bhutan and east Nepal, as well as Japan and Taiwan, but no very notable new species have been found. In recent years tourists have been allowed into parts of western China and Bhutan and some good forms have been seen of well known species. Good relations are being established with the Chinese botanists in Kunming and some good books have been published by them on the rhododendron species in China.
Over a number of years, my father sent seed of his hybrids and of species which he had raised from Chinese seed to Joseph Gable of Stewartstown, Pennsylvania, to Herr Dietrich Hobbie in Germany and to Koichiro Wada in Japan. In this way, the good blue form of R. augustinii (Wilson #4238) has come into general cultivation.
In the spring of 1964, we had a visit from Dr. Milton Walker and at his request sent cuttings to the Botanical Garden in Vancouver, British Columbia, Canada, notably of R. longesquamatum for grafting and despatch to the Rhododendron Species Foundation, then in formation in the USA.
The Rhododendrons of Sikkim-Himalaya, J.D. Hooker, 1849-51.
Rhododendrons and Their Various Hybrids, Volume I, J.G. Millais, 1917.
The Rhododendron Society Notes, Volume II, No.1, 1920; Volume II, No.5, 1924; Volume III, No.1, 1925.
The Species of Rhododendrons, edited by J.B. Stevenson, 1930.
Plant Hunting in China, E.H.M. Cox, 1945.
Trees and Shrubs Hardy in the British Isles, Volume III, 8th edition, W.J. Bean, 1976.
Rhododendrons with Magnolias and Camellias 1979-80 "Rhododendrons - the Early History of Their Introduction and Cultivation in Britain," Lawrence P. Mills.
Rhododendron Species, Lepidotes, Volume I, H.H Davidian, 1982.
Walter Magor is a member of the Royal Horticultural Society and serves on the editorial board of the RHS Rhododendron Group. He frequently contributes articles to the RHS Rhododendron Group's annual bulletin and other publications.
This article first appeared in the Cornish Garden Journal and is reprinted here with their kind permission.