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 watsonii' from the website Trees and Shrubs Online (treesandshrubsonline.
Shrub or small tree, 2–6 m. Leaves 10–23 × 4.3–10 cm, obovate to oblanceolate, apex acute to acuminate, lower surface covered with a whitish thin compacted and agglutinated indumentum; petioles to 5 mm, stout and flattened. Flowers 12–15, in dense truss, c.7-lobed, white, with a crimson basal blotch, campanulate, nectar pouches lacking, 35–40 mm; stamens 14; ovary glabrous. Flowering March-April. Royal Horticultural Society (1997).
Distribution China Gansu, Sichuan
Habitat 2,600–3,300 m
RHS Hardiness Rating H4
Conservation status Near threatened (NT)
Taxonomic note A distinctive species on account of its short flattened petioles. It is allied to R. balangense. Royal Horticultural Society (1997)
An evergreen shrub or small tree, sometimes 30 ft high in the wild; young shoots stout, often 5⁄8 in. in diameter, scurfy white when young, becoming yellowish. Leaves oblanceolate to obovate, abruptly narrowed at the apex to a short point, tapered at the base to a thick, winged, yellowish stalk that is up to 1 in. long and 1⁄2 in. wide, 6 to 9 in. long, 2 to 4 in. wide, dark dull green and glabrous above, covered beneath with a pale, very close scurf; midrib broad and yellow above. Flowers produced from February to April in trusses of twelve to eighteen blooms and about 6 in. wide. Calyx small, 1⁄12 in. long, with even triangular teeth; flower-stalks 1 to 11⁄2 in. long, thinly downy. Corolla bell-shaped, 2 in. wide, nearly as deep, seven-lobed, white with a small purple blotch at the base. Stamens fourteen, shorter than the corolla, their white stalks downy towards the base. Ovary and style glabrous. (s. Grande)
Native of W. Szechwan; discovered by Wilson in 1904 and introduced by him. It is a little-known species, rare in cultivation, which is placed in the Grande series, of which it is an aberrant member, differing from all the other species, except R. peregrinum, in its glabrous ovary; the petiole is very short, with the decurrent base of the blade forming a wing on either side, as in R. praestans. During his second expedition for the Arnold Arboretum Wilson collected seed from trees 25 to 30 ft high, with trunks 2 to 21⁄2 ft in girth.
R. peregrinum, mentioned under this species on page 803, is probably a natural hybrid of R galactinum (Rev. 2, p. 431).