An evergreen shrub up to 20 ft high in the wild, the quite young shoots clothed with a loose, white scurf, or sometimes glabrous. Leaves oblong-lanceolate, tapered at the base, pointed, 21⁄2 to 5 in. long, 1⁄2 to 11⁄4 in. wide, glabrous and bright green above, the lower surface covered with a close white scurf; stalk 1⁄2 in. or less long. Flowers borne in May in a lax truss of as many as twelve; flower-stalks slender, up to 11⁄2 in. long. Calyx small, with glabrous triangular lobes. Corolla white blush or pink, more or less spotted with pink on the upper lobes, broadly funnel-shaped, about 11⁄2 in. wide. Stamens twelve or fourteen, shorter than the corolla, white with down at the base (but glabrous in var. leiandrum Hutch.). Ovary downy; style glabrous. Bot. Mag., t. 8767. (s. Arboreum ss. Argyrophyllum)
Native of W. Szechwan; discovered by the Abbé David in 1869 near Mupin; introduced by Wilson in 1904. It is a fine species at its best, with flowers of a delicate pink very freely borne, and makes a well-shaped narrow bush. It is also very distinct in the pure white undersurface of the young leaves. It is a variable species. Typically, the flowers are narrowed to the base, but in var. cupulare Rehd. they are nearer to cup-shaped. The leaves may be rounded at the base, not tapered as described above for the more typical form. Award of Merit May 1, 1934, when shown by Gerald Loder, Wakehurst Place, Sussex (this may have been var. cupulare).
var. nankingense Cowan – Leaves larger, very silvery white beneath, and with large trusses of pink flowers, which are more than 2 in. across. Found by A. N. Steward on the Lao Shan, Kweichow province, in 1931, and introduced by him to the Edinburgh Botanic Garden in the following year. Award of Merit April 30, 1957, when shown by the Crown Estate Commissioners, Windsor Great Park (clone 'Chinese Silver').
R. hypoglaucum Hemsl. – A close ally of R. argyrophyllum, perhaps a geographical subspecies. It is found to the east of R. argyrophyllum, in N.E. Szechwan and Hupeh, and according to Wilson, who introduced it in 1900, it is locally abundant in thin woods or, at its altitudinal limit, growing in open country among rocks, and attaining a height of 20 ft and as much in width. The flowers are white or pink, more or less spotted, sometimes densely so, rather like those of R. argyrophyllum var. cupulare in shape, borne in May. The main distinction from its ally seems to be that the leaves are relatively broader, 2 to 4 in. long, 1 to 11⁄2 in. wide, and the ovary is usually glandular as well as hairy. Bot. Mag., t. 8649.
From the Supplement (Vol. V)
subsp. nankingense (Cowan) Chamberlain R. a. var. nankingense Cowan
subsp. hypoglaucum (Hemsl.) Chamberlain R. hypoglaucum Hemsl.
The var. cupulare, mentioned in the second paragraph (page 600), is included by Chamberlain in the typical part of R. argyrophyllum, which is variable in the shape of the corolla (rev. 2., p. 325).
† R. pingianum Fang – Near to R. argyrophyllum but leaves longer than in the typical state of that species, the flowers deeper pink, and the ovary eglandular and coated with a rusty tomentum. Native of central-western Szechwan. It occurs on Mount Omei (Emei Shan) and is now in cultivation from seeds collected on the mountain by Keith Rushforth and by Roy Lancaster in 1980.
More remote from R. argyrophyllum, but resembling it in many respects, is R. formosanum Hemsl. The leaves are relatively much narrower, 3 to 6 in. long and never much over 1 in. wide, with a thicker indumentum beneath and on the average with more flowers in the inflorescence. Described in 1895 from a specimen collected by Augustine Henry, it was introduced to Britain in 1973 through John Patrick's 'Rhododendron Venture'. It is an inhabitant of broad-leaved forest up to about 6,500 ft, making a tall shrub or small tree, and will probably prove tender.