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 keysii' from the website Trees and Shrubs Online (treesandshrubsonline.
Straggling shrub, 1–3.5 m; young shoots scaly. Leaves 6–10(–15) × 1.9–3(–3.6) cm, elliptic, apex acute, lower surface densely covered with close to distant unequal flat broad-rimmed scales. Flowers pendulous, 2–5 per inflorescence, the individual inflorescences often fusing together; calyx minute; corolla tubular, deep red to salmon pink, lobes usually yellow, (14–)20–25 mm; stamens 10, decimate; ovary scaly, slightly pubescent at top, style declinate, pubescent towards base. Flowering June-July. Royal Horticultural Society (1997).
Distribution Bhutan China S Tibet India Sikkim, Arunachal Pradesh
Habitat 2,440–3,650 m
RHS Hardiness Rating H5
Awards AM 1933 (L. de Rothschild, Exbury) as var. unicolor, from Kingdon-Ward 6257; flowers Carthamus Red, tips of corolla lobes slightly yellowish.
Conservation status Least concern (LC)
An evergreen shrub 6 ft or more high; the young shoots, the undersurface of the leaves, leaf-stalk, and flower-stalk densely covered with brownish-red, glistening scales. Leaves 2 to 4 in. long, 5⁄8 to 11⁄4 in. wide, oval-ovate, tapering at both ends; stalk 1⁄3 to 2⁄3 in. long. Flowers crowded in short clusters, several of which are borne during May and June from buds near the end of the previous year’s shoot, and at the time of flowering surmounted by the young shoot of the current year. Each flower is 3⁄4 to 1 in. long, 1⁄4 in. wide – a brick-red, cylindrical tube with five small, blunt, yellow teeth at the mouth; calyx very small; flower-stalk 1⁄4 in. long. Bot. Mag., t. 4875. (s. Cinnabarinum)
Native of the eastern Himalaya, from Bhutan to the region of the Tsangpo bend; introduced by Booth from Bhutan in 1851. But most of the plants now in collections derive from seed collected by Kingdon Ward in the early winter of 1924 in Pemako, S.E. Tibet, on the southern side of the Doshong La, where it grows in thickets on the southern slopes of the valley or as undergrowth in the forest at 9,000 to 10,000 ft. These plants (KW 6257) are hardier than the form originally introduced from Bhutan but the species, although of some value for its late flowering, is really little more than a botanical curiosity. It is allied to R. cinnabarinum, but the flowers are much smaller, correa-like, and produced from axillary as well as terminal buds.
Award of Merit June 27, 1933 to a form raised from KW 6257 in which the flowers are uniform red except for a slight yellow tinge at the tips, shown by Lionel de Rothschild, Exbury. It was named var. unicolor by Hutchinson.