A sturdy evergreen shrub 4 to 12 ft high in cultivation, usually wider than it is high, but described in the wild as a tree-like shrub 15 to 20 ft high; young shoots thick, and clothed with a soft white felt. Leaves narrowly oblong, tapered at the base, blunt at the apex, 4 to 7 in. long, 1 to 2 in. wide, thick and leathery, dark green, soon becoming glabrous above; lower surface covered with a thick, soft felt, at first almost pure white, finally pale brown; stalk 1⁄4 to 3⁄4 in. long. Flowers produced during May or June in fine trusses 4 to 6 in. through; pedicels 1 to 11⁄2 in. long, slightly downy. Calyx very small, with five rounded lobes. Corolla bright purplish rose 2 to 3 in. across, broadly funnel-shaped, the five rounded lobes with beautifully frilled margins. Stamens ten, downy at the base. Ovary clad with white wool; style glabrous. Bot. Mag., t. 7495. (s. Ponticum ss. Caucasicum)
Native of north-east Asiatic Turkey, especially around Artvin on the river Coruh, where it reaches to the tree-line; it is not certain whether it also occurs in bordering parts of Russia. It was discovered by Baron Ungern-Sternberg in 1885 and introduced to Kew the following year by way of St Petersburg. The species is distinct in the very thick white felt on the lower surface of its leaves, resembling in this respect R. ungernii and species of the Argrophyllum subseries of the Arboreum series. It is perfectly hardy, and would be more valued if it had come from China. Some plants distributed as P. smirnowii are R. ungernii.
R. smirnowii and R. ungernii are of botanical interest as relict species, more closely allied to east Asiatic rhododendrons than to their neighbours. R. ponticum and R. caucasicum.
From the Supplement (Vol. V)
This species does occur in Russia (cf. the second paragraph on page 773). See the article by M. S. Alexandrova in Rhododendron Notes and Records, Vol. 1 (1984), pp. 137-46, for this species and R. ungernii.