Species In Our
This lovely lepidote (scaly-leaved) rhododendron is a member of Subsection Lapponica. It is most closely related to R. rupicola. The specific name 'russatum' means 'reddened' from the red-brown or rust-colored scales which almost completely cover the underside of the leaves. The plant was first described by George Forrest in 1917 when he found it on the Kari Pass in NW Yunnan, China at 9000 feet. The plant is found in N and NW Yunnan and SW Sichuan, as well as Upper Burma in alpine pasture, forest margins, cliffs, and limestone scree at elevations of 11,000-14,000 feet.
R. russatum is a small shrub of 6 inches to 5 feet in height, of varying compactness and form; it can be upright, compact, cushion, semi-prostrate or straggly. The leaves are rusty-green, usually oval, up to 1 3/4 inches long and have a rounded tip with a sharp point or mucro; they are glabrous (hairless). The scales on the underside of the leaves are so dense and contiguous that they clearly color the leaf undersides. The leaf petioles and the branchlets are also densely scaly. The little terminal trusses have up to 6 flowers, widely funnel-form up to 3/4 inches long and colored deep purple-blue, red-purple, purple, pink or rose. There are usually 10 stamens the length of the corolla.
Forrest himself and Rock collected a number of distinct forms of R. russatum. Various forms with compact growth and intense flower color have earned Awards of Merit and a deep purple form exhibited by Lionel de Rothschild took a First Class Certificate in 1933. There is no need to grow inferior forms since excellent plants with superb flower color are available commercially. Greer lists russatum as hardy to -15°F, easy enough in the Boston area. Like most Lapponica it has more trouble with the heat of summer than the cold of winter and appreciates alpine treatment with excellent drainage and a cool root run. It blooms before the major number of rhododendrons. R. russatum belongs in every garden for its unsurpassed, distinctive deep color; with its compact habit and small leaves it is an excellent foreground or rock garden plant worthy of a choice spot.
There are quite a number of crosses with R. russatum as breeders have used its intense, deep color and good plant habit. Crossed with ‘Blue Diamond’: ‘Amethyst’, ‘Azurwolke’, ‘Blue Chip’, ‘Cobalt’, ‘Gletschernacht’, ‘Hydon Mist’; with R. augustinii: ‘Russautinii’ and its back cross to R. augustinii, ‘Blue Ridge’; and with R. impeditum: ‘Azurika’ and ‘Hachmann's Violetta’. At the ARS convention held in Boston, Weston Nurseries introduced ‘Blue Baron’ with its R. russatum parentage.
Susan Clark, Concord, MA