A dwarf evergreen shrub, forming in the wild broad spreading mats 6 to 20 in. high, more rarely erect and up to 5 ft high; younger branches thickly set with roundish-ovate, membranous scales (perulae) up to 1⁄4 in. long, which persist for several years. Leaves oval-obovate, more tapered to the base than the apex, 3⁄4 to 11⁄2 in. long, 1⁄2 to 5⁄8 in. wide, dark green above, glaucous-white and nearly glabrous beneath; very shortly stalked. Flowers produced in clusters of three to six. Corolla between funnel- and bell-shaped, 11⁄2 to 13⁄4 in. long, scarcely as much wide, varying in colour from white to different shades of rose, orange-red, and yellow. Stamens ten, 3⁄4 in. long, glabrous. Ovary covered with branched hairs and usually with glandular bristles also. Calyx with small glands on the margins of the shallow lobes; flower stalks 1⁄2 to 5⁄8 in. long, downy. Bot. Mag., t. 9507. (s. Neriiflorum ss. Sanguineum)
R. aperantum was discovered by Kingdon Ward in 1919 on the western spur of Imaw Bum, a mountain in N.E. Burma on the divide between the eastern Irrawaddy (Nmai Hka) and the Salween, and was introduced by him in the same year. But the type of the species was collected by Farrer in the following year on the Chawchi pass, farther to the north on the same divide, a few months before his death. He wrote of it: 'it is simply one of the most radiantly lovely things you ever saw, and when you do see it, your mouth just opens and shuts feebly. It is common, in drifts and sheets; and, for the altitude, and for its stature, rather large in all its parts. In stature it ranges from half an inch, or less, to about six inches, spreading widely, and often plastered flat against a rock, where starved. The flowers . . . are very large, and in a sequence of the most glorious warm pink tones – absolutely clean of mauve or blue shades – through hot flesh-pinks, rose-pinks, salmon-pinks, to flushed snow and pure white' (Gard. Chron., Vol. 70 (1921), p. 209).
Most of the plants in cultivation are from seeds sent by Forrest between 1925 and 1931 from the same part of Burma and from bordering parts of China. Unfortunately, R. aperantum has proved a sad disappointment in cultivation, as it flowers poorly. Probably a moist position with abundant sky-light but protected from the strongest sun would suit it best. A crimson-flowered form received an Award of Merit in 1931, when shown by Lord Headfort from his garden in Ireland.