An evergreen shrub 6 ft high in the wild; young branches slightly scaly. Leaves 11⁄2 to 21⁄2 in. long, 3⁄4 to 11⁄4 in. wide, oval-oblong, pointed at the apex, rounded or tapered at the base, more or less scaly on both surfaces, but especially beneath; stalk about 1⁄4 in. long. Flowers pale, rather dull yellow, 11⁄4 to 2 in. across, in clusters of about four or five; corolla broadly bell-shaped; calyx undulated into five very shallow lobes; stamens ten, slightly downy; flower-stalk scaly, 1⁄2 to 3⁄4 in. long. Blossoms in April and May. Bot. Mag., t. 8300. (s. and ss. Triflorum)
Native of Japan from the main island southward as far as Yakushima; introduced in 1908 and quite hardy. It is a rather variable species, both in habit and in the size and shape of its leaves. In his collection at The Grange, Benenden, Kent, Capt. Collingwood Ingram has a tall-growing plant which he considers to be a good match for typical R. keiskei, in which the leaves are lanceolate, acute, up to 3 in. long and 3⁄4 in. wide, and the petioles bristly when young. The commonly cultivated form, by contrast, is of low-growing habit and has shorter and relatively broader leaves, which are obtuse or subacute at the apex, with a stout midrib and glabrous petioles. Ingram considers the latter to represent a distinct species, which he has named R. laticostum (R.C.Y.B. 1971, pp. 28-30). These two cultivated forms are certainly very distinct, but the difference would probably be much less clear-cut if a wide range of wild specimens were examined. In the same article, Ingram published a second species, R. trichocalyx, described from a cultivated plant. He informs us that he is now satisfied that the plant in question is a hybrid of garden origin.
cv. 'Yaku Fairy'. – A prostrate plant with flowers about 13⁄4 in. across in trusses of two to five. Leaves lanceolate, up to 11⁄2 in. long. Award of Merit April 14, 1970, when shown by Barry N. Starling. It was collected on Mt Kuromi, Yakushima (see R.C.Y.B. 1971, pp. 104-6).