An evergreen shrub said occasionally to be 15 to 25 ft high in the wild; but considerably less at present in cultivation; young shoots glabrous. Leaves glabrous, oval to oblong-ovate, rounded at the base and abruptly narrowed to a mucro at the apex, 21⁄2 to 5 in. long, about half as much wide; dull green above, rather glaucous beneath; stalk 3⁄4 to 11⁄4 in. long. Flowers not fragrant, opening in May in rather loose trusses of about ten. Calyx small, fleshy, being only an unequal-sided development of the flower-stalk, which is about 1 in. long and glandular. Corolla widely funnel-shaped, 21⁄2 in. wide, pale clear rose, seven-lobed. Stamens fourteen, glabrous. Ovary densely glandular, the style also densely furnished over its whole length with dark red glands. Bot. Mag., tt. 8834, 8904-5. (s. and ss. Fortunei)
Native of Szechwan and Yunnan, where it is widely distributed; discovered by the French missionary Soulié about 1889 west of Kangting (Tatsien-lu); introduced by Wilson in 1904, and also cultivated from seeds sent later by Forrest, Kingdon Ward, Rock, and Yu. It is allied to R. decorum but can always be distinguished from it (and from other members of the Fortunei subseries) by the remarkable red glands on the style.
R. vernicosum is somewhat variable. Four species are sometimes referred to as 'geographical forms' of R. vernicosum and maintain a shadowy existence, though all four were considered as synonymous with R. vernicosum by Dr Cowan. Of these, R. araliaeforme was described from specimens collected by Forrest in Tsarong province, S.E. Tibet, and the plants cultivated under this name were from seeds he sent home from this area in 1919; the plants called R. euanthum and R. rhantum were from seeds collected in the Lichiang range; and R. sheltonae is the name by which the Wilson introduction from W. Szechwan was originally known.
The specific epithet, which means 'varnished', seems very unfitted for a dull-leaved plant like this. But a varnished appearance can be developed by heating the surface of the leaf, which is, probably, what had been done when drying the original specimens on which Franchet based his description.
R. vernicosum is a beautiful and quite hardy species. Some forms do not flower until May and these are the best for frosty gardens. The Award of Merit was given in 1964 to clone 'Loch Eck', when exhibited from the Younger Botanic Garden, Benmore, Argyll, on April 14. The clone 'Sidlaw' received a Preliminary Commendation when shown by E. H. M. and P. A. Cox on May 19, 1969.