Rhododendron keysii Nutt.

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Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron keysii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-keysii/). Accessed 2020-12-02.

Genus

Synonyms

  • Rhododendron igneum Cowan

Other species in genus

Glossary

Tibet
Traditional English name for the formerly independent state known to its people as Bod now the Tibet (Xizang) Autonomous Region of the People’s Republic of China. The name Xizang is used in lists of Chinese provinces.
axillary
Situated in an axil.
calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
ovate
Egg-shaped; broadest towards the stem.

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron keysii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-keysii/). Accessed 2020-12-02.

Straggling shrub, 1-3.5 m; young shoots scaly. Leaves 6-10(-15) x 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  BhutanChina 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)

Taxonomic note Including var. unicolor Hutch. & R. igneum Cowan Royal Horticultural Society (1997)

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, 58 to 114 in. wide, oval-ovate, tapering at both ends; stalk 13 to 23 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 34 to 1 in. long, 14 in. wide – a brick-red, cylindrical tube with five small, blunt, yellow teeth at the mouth; calyx very small; flower-stalk 14 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.