Dwarf prostrate shrub, to 0.6(-l) m; young shoots sparsely scaly, glabrous or pubescent. Leaves (1–)1.4–2.5(–3.5) × (0.4–)0.7–1.2 cm, apex obtuse to (rarely) subacute, upper surface pubescent along midrib; lower surface whitish- or silvery-papillose, glabrous but with scattered deciduous vesicular scales. Pedicels 25–50 mm, elongating to 75 mm in fruit, sparsely scaly and pubescent. Flowers 1–2(–3)-flowered; calyx lobes usually 4–7 mm, oblong or obovate; corolla pink to red or purple, pruinose, campanulate, (10–)13–20(–23) mm, tube glabrous outside, sparsely pubescent within; stamens 10; ovary sparsely scaly, impressed below the sharply deflexed style. Flowering May-June. Royal Horticultural Society (1997)
Distribution Myanmar NE China S Tibet, Yunnan India Arunachal Pradesh
Habitat 2,750–4,250(–4,900) m
RHS Hardiness Rating H5
Awards AM 1973 (Capt. c. Ingram, Benenden, Kent) to a clone 'Baby Mouse'; flowers deep plum purple. AM 1971 (Crown Estate Commissioners, Windsor) to a clone 'Bodnant Red', as var. cremastum; flowers greyed-purple. AM 1966 (Capt. c. Ingram, Benenden, Kent) to a clone 'Thimble', as var. cremastum; flowers salmon pink. AM 1925 (L. de Rothschild, Exbury) as var. myrtilloides. FCC 1943 (E. de Rothschild, Exbury) as var. myrtilloides; flowers Magenta Rose. AMs have been awarded to the clones 'Leucanthum' and 'Beryl Taylor'; both are now considered to be hybrids of R. campylogynum.
Conservation status Least concern (LC)
Taxonomic note A distinct species, assigned to its own subsection. Royal Horticultural Society (1997)
A usually dwarf, evergreen shrub of densely branched, close growth; young shoots thinly scaly. Leaves obovate, tapered at the base, rounded but with a short mucro at the apex; margins recurved and crinkled, 1⁄3 to 1 in. long, 1⁄8 to 1⁄2 in. wide, dark bright green and glabrous above, pale green or slightly glaucous beneath and slightly scaly at first; stalk 1⁄10 in. long. Flowers solitary or in twos or threes at the end of the shoot, nodding, each produced on a slender, slightly scaly stalk 1 to 11⁄2 in. long. Calyx five-lobed; the lobes 1⁄5 in. long, glabrous. Corolla of various shades of purple from rosy to plum-coloured or almost black purple, widely bell-shaped, 5⁄8 in. long, five-lobed, the lobes rounded and scarcely recurved. Stamens ten (sometimes eight or twelve), downy and widened towards the base; anthers yellowish brown. Ovary glandular-scaly; style glabrous, purple, decurved so as to protrude between the lower lobes of the corolla. Bot. Mag., t. 9407A. (s. Campylogynum)
R. campylogynum ranges throughout the rainiest part of the Sino-Himalayan region, from the Tali range and the Mekong-Salween divide in the east through upper Burma to the eastern Himalaya, at altitudes of 11,000 to 15,000 ft (rarely lower). It is therefore one of the most alpine of rhododendrons. It was discovered by the Abbé Delavay in 1884 in the Tali range, whence it was introduced by Forrest in 1912. In the following year Kingdon Ward collected seeds near one of the glaciers of the Ka-kar-po group, on the borders between Yunnan and Tibet. The plants there ‘appeared to have black or deep plum-coloured flowers. When, however, the sun shone through them, the flowers were seen to be blood-red, which is how they would appear to their bee-visitors, since the flowers stand horizontally’ (Mystery Rivers of Tibet, p. 75).
This pleasing species flowers in May and is admirable for the rock garden by reason of its neat habit and rich purple flowers. In some forms, however, the flowers are purplish pink or flesh-pink. In the clone named ‘Thimble’, they are salmon-pink (Award of Merit, May 23, 1966, when shown by Capt. Collingwood Ingram, The Grange, Benenden, Kent).
A white-flowered form of R. campylogynum, grown by Capt. Collingwood Ingram at Benenden, Kent, received an Award of Merit when he exhibited it on June 12, 1973. He has given it botanical status as var. leucanthum (R.C.Y.B. 1969, p. 49) and it received the award under that name.
Dr Cullen recognises no subspecies or varieties in this species, on the grounds that the variations it shows are not correlated nor ‘geographically significant’ (Rev. 1, pp. 145–6). The varieties previously recognised could, however, be maintained as horticultural groups (see Peter Cox, op. cit., p. 88).
R. charopoeum Balf. f. & Farrer
R. caeruleo-glaucum Balf. f. & Forr
R. cremastum Balf. f. & Forr
R. myrtilloides Balf. f. & Ward