Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998
Article from Bean's Trees and Shrubs Hardy in the British Isles
'Rhododendron rupicola' from the website Trees and Shrubs Online (treesandshrubsonline.
Much-branched dwarf shrub, to 0.6(-1.2) m. Leaves 0.7-2 x 0.3-1.3 cm, broadly elliptic to ovate, apex rounded, mucronate, lower surface covered with overlapping to slightly separated, predominantly dark brown (though with some amber to pale golden) scales. Flowers to 6 per inflorescence; calyx lobes 3-6 mm, oblong or broadly ovate, with a central band of scales; corolla usually an intense purple or yellow, occasionally deep crimson, magenta, or even white, broadly funnel-shaped, (8-)10-16(-18) mm; stamens 5-10, about as long as the corolla; ovary entirely pubescent or with scales on the upper half and a tuft of hairs at the apex, style longer than the stamens, glabrous or pubescent at base. Flowering April-May. Royal Horticultural Society (1997)
Distribution Myanmar N China SE Tibet, W Yunnan, SW Sichuan
Habitat 3,000-4,875 m
RHS Hardiness Rating H6
Conservation status Least concern (LC)
An evergreen shrub 2 to 4 ft high, young shoots, leaves (on both sides), outside of calyx-lobes, ovary, and flower-stalks all very scaly. Leaves oval, often inclined to oblong, rounded but with a tiny mucro at the apex, 1⁄2 to 3⁄4 in. long, 1⁄6 to 1⁄3 in. wide, dark green above, yellowish grey between the scales beneath; stalk 1⁄12 to 1⁄8 in. long. Flowers opening in April and May in a terminal cluster of three to five, each on a very short stalk. Calyx 1⁄6 in. long, deeply five-lobed, the lobes oblong, deep purple, fringed at the margin. Corolla 7⁄8 in. wide, of a rich plum-purple, the tube very short and clothed inside with white hairs, five-lobed, the lobes ovate-oblong, rounded at the end, spreading, sprinkled more or less with scales outside, mostly up the middle. Stamens normally ten, but sometimes as few as seven, purple, 1⁄2 in. long, tufted with white down near the base; anthers pale brown. Ovary scaly towards the top; style overtopping the stamens, purple, glabrous. (s. Lapponicum)
Native of N.W. Yunnan and S.W. Szechwan at 12,000 to 14,000 ft; discovered by Forrest in 1910 in the Lichiang range and introduced by him in the same year. Its flowers, although small, are of a wonderfully rich purple, this colour extending to the style and the filaments of the stamens. R. russatum, which often bears flowers of a similar colour, differs in having much larger leaves and a downy style. R. rupicola is perfectly hardy.
var. chryseum (Balf.f. & Ward) Philipson & Philipson – See R. chryseum, page 629; also Davidian, The Rhododendron Species, Vol. 1, pp. 177-9 (as R. chryseum), where the forms in cultivation are discussed. The variety is variable in the number of stamens.
var. muliense (Balf.f. & Forr.) Philipson & Philipson R. muliense Balf.f. & Forr. – Considered in recent years to be synonymous with R. chryseum, R. muliense is recognised as a distinct variety of R. rupicola by the Philipsons, similar in flower-colour to var. chryseum, but having the calyx-lobes margined with both hairs and scales (against hairs only in var. chryseum and var. rupicola), and with the leaves often narrowly oblong rather than elliptic. The traditional method of distinguishing the two species, as they once were, namely five stamens in R. chryseum and ten in R. muliense, does not work, since var. chryseum varies in the number of its stamens, though it is the case that they are fairly consistently ten in var. muliense (Rev. Lapp., pp. 62-3).
[R. achroanthum] – Included in R. rupicola.
R. propinquum Balf. f. & Ward
R. chryseum Balf.f. & Kingdon-Ward
Corolla yellow; calyx lobes margined with scales and hairs. Royal Horticultural Society (1997)
RHS Hardiness Rating: H6
Corolla yellow; calyx lobes margined with hairs only. Royal Horticultural Society (1997)
This species is closely allied to R. russatum but may be distinguished by the presence of a central band of scales on the corolla lobes. It usually also has rather smaller leaves.
Corolla purple to crimson, rarely white.
Distribution N Burma, China (SE Tibet, Yunnan, SW Sichuan).
Habitat to at least 4,000m.
Taxonomic note (incl. R. achroanthum Balf.f. & W.W.Sm)