An evergreen shrub varying from 8 to 20 ft high in the wild; young shoots soon becoming glabrous. Leaves elliptic-lanceolate or oblanceolate, tapered about equally towards both ends but terminated by a short slender point, 3 to 51⁄2 in. long, 1 to 13⁄4 in, wide, glabrous and green on both surfaces; stalk 1⁄2 to 5⁄8 in. long. Flowers borne during May in a racemose cluster of about eight; pedicels about 3⁄8 in. long. Calyx a mere wavy rim. Corolla tubular-campanulate, 2 in. long, 11⁄2 in. wide, deep crimson with darker spots, five-lobed, the lobes notched. Stamens ten, glabrous or slightly downy at the base; ovary and style glabrous, the latter much longer than the stamens and standing out well beyond the corolla. (s. and ss. Irroratum)
Native of the Yunnan-Burma borderland westward through upper Burma to the Mishmi Hills, Assam, and the region of the Tsangpo gorge; also of Thailand; discovered by Kingdon Ward above Hpimaw, upper Burma, and introduced by Farrer and Cox five years later from the same locality, where it grows at about 8,000 ft. In the typical form the flowers are crimson or crimson-scarlet, but other colours have been recorded by Kingdon Ward and Forrest in their field notes, e.g., ‘black crimson’, ‘light or dark amethyst purple’, or ‘morose purple’. It is found at altitudes between 6,000 and 11,ooo ft and is tender in some forms. It is not of much ornamental value, even the crimson forms having a hint of magenta in their colouring.
R. kendrickii Nutt. – This imperfectly known species was described by Nuttall in 1853 from a specimen collected by his nephew Thomas Booth in the Assam Himalaya, just east of the Bhutan frontier. The type-specimen is of foliage and fruit only, and no plant has been traced which is known for certain to have been raised from the seed Booth collected. The amplified description of R. kendrickii in Notes Roy. Bot. Gard. Edin., Vol. 10, pp. 107-8, is based mainly on specimens collected by Cooper in Bhutan. The leaves are leathery, relatively narrow, being up to 6 in. long but not much over 1 in. wide, with wavy margins, glabrous beneath except for flock on the midrib. Truss dense, many-flowered. Corolla pink and spotted in the Cooper specimens, but dark red and unspotted in Cox and Hutchison 416, collected in 1965 in the Apa Tani valley, some 120 miles east of the type-locality (the specimen under this number perfectly matches the type in foliage). Ovary sparsely hairy, sometimes glandular.
In 1924 Kingdon Ward collected seed in the Tsangpo gorge of a rhododendron which, from the fruiting specimen, was identified as R. kendrickii, under which name the seed was distributed (KW 6284). However, a plant raised from this seed by Sir John Ramsden at Bulstrode Park was described by Cowan in 1936 as a new species – R. ramsdenianum. It is very near to R. kendrickii, however.