An evergreen shrub of lax habit, often found in nature as an epiphyte on various species of trees; young shoots slightly scaly, otherwise glabrous. Leaves oblong to oval, rounded at both ends, 21⁄2 to 6 in. long, 3⁄4 to 2 in. wide; glaucous and scaly beneath; stalk 3⁄4 in. long. Flowers in clusters of four to eight, fragrant. Calyx 5⁄8 in. long, deeply five-lobed, the lobes oblong-ovate fringed with whitish hairs; flower-stalk 1⁄2 in. long, scaly, not downy. Corolla white, funnel-shaped, 3 to 31⁄2 in. long and wide, five-lobed. Stamens ten, very downy at the lower half. Ovary and base of style thickly covered with red-brown scales. Bot. Mag., n.s., t. 363. (s. Maddenii ss. Megacalyx)
Native of the eastern Himalaya as far west as E. Nepal and of the Mishmi Hills, the Naga Hills, and Manipur; described in 1864 from a plant growing in Standish's nursery, where it had been raised from seeds collected in the Himalaya. As it later turned out, J. D. Hooker had found it in 1848-9 in Sikkim and the Darjeeling region but confused it with R. dalhousiae. R. lindleyi, at least under its correct name, remained a rare species in gardens until Kingdon Ward reintroduced it in 1928 from the Delei valley in the Mishmi Hills, where he found it as a slim shrub sometimes 10 to 12 ft high growing in thickets on an exposed cliff with eleven other species of rhododendron, at 9,000 ft (KW 8546). It is also in cultivation from seed collected by Ludlow and Sherriff in the Tibetan Himalaya, in 1936, from plants up to 15 ft high, growing at 7,000 to 8,500 ft.
R. lindleyi is one of the most beautiful species of the genus, with flowers of an exquisite fragrance that Thomas Moore, in his original description, likened to a mixture of lemon and nutmeg. It has to be grown in a cool greenhouse over much of the country, but flourishes in the open in many gardens on the west coast of Scotland and in other parts of the Atlantic zone. It is by nature a straggly shrub and therefore best grown on a wall or mixed with other rhododendrons of almost the same height. But on the Isle of Gigha, off the coast of Argyll, there are plants grown fully in the open which are of compact habit (R.C.Y.B. 1958, fig. 5).
The Kingdon Ward introduction from the Mishmi Hills received an Award of Merit in 1935, when shown from Exbury on April 14, 1935, and a First Class Certificate two years later, on this occasion exhibited by Adm. Heneage-Vivian, on May 4. More recently the Award of Merit has been given to two clonal forms of R. lindleyi: to 'Dame Edith Sitwell', shown by Geoffrey Gorer, Sunte House, Haywards Heath; and to 'Geordie Sherriff', raised and shown by Mr A. C. and Mr J. F. A. Gibson, Glenarn, Rhu, Dunbartonshire.
R. dalhousiae Hook. f. – This species, originally confused with R. lindleyi, differs from it in the young shoots being bristly as well as scaly, in the downy flower-stalks, in the calyx-lobes not being fringed with hairs, and in the style being scaly for about two-thirds of its length from the base. It is a native of the Himalaya trom E. Nepal to Bhutan, and was discovered by Hooker in Sikkim in 1848. Bot. Mag., t. 4718. It is rather less hardy than R. lindleyi and not superior to it in any respect, so less common in gardens. Award of Merit 1930, as a shrub for the cool greenhouse. It flowers in May or June. The flowers vary in colour from white to pale yellow or greenish yellow.
R. rhabdotum Balf. f. & Cooper – Very closely allied to R. dalhousiae, scarcely differing except in the colour of the corolla, which has strips of crimson running down the outside of each lobe along the median rib. Bot. Mag., t. 9447. It was described in 1917 from a flowering specimen collected two years previously by Roland Cooper in Bhutan. Cooper found it in the Punakha valley, growing as a tree 12 ft high at 8,000 ft, on dry rock faces; his specimer s of R. dalhousiae, collected in the same area, were from 6,500 ft. R. rhabdotum was introduced by Kingdon Ward in 1925, who collected seed 'blind' in February near the border between Bhutan and Assam, while on the way home from his famous exploration of the Tsangpo gorge and the mountains around it (KW 6415). The plants from which he took the seed were sprawling shrubs 2 to 3 ft high, growing by the Nyamjang river. Ludlow and Sherriff later reintroduced it from the same part of the Himalaya and also from Bhutan. It is a definitely tender species, but is grown in the open in a few gardens in the mildest parts.
From the Supplement (Vol. V)
R. rhabdotum, mentioned under this species on page 709, becomes R. dalhousiae var. rhabdotum (Balf.f. & Cooper) Cullen. It is portrayed in David-ian, The Rhododendron Species, Vol. I, plate 46.