Rhododendron sperabile Balf. f. & Farrer

TSO logo

Sponsor

Kindly sponsored by Peter Norris, enabling the use of The Rhododendron Handbook 1998

Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron sperabile' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-sperabile/). Accessed 2020-08-07.

Genus

Infraspecifics

Other species in genus

Glossary

calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
Tibet
Traditional English name for the formerly independent state known to its people as Bod now the Tibet (Xizang) Autonomous Region of the People’s Republic of China. The name Xizang is used in lists of Chinese provinces.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glandular
Bearing glands.
lanceolate
Lance-shaped; broadest in middle tapering to point.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.

References

There are currently no active references in this article.

Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron sperabile' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-sperabile/). Accessed 2020-08-07.

Shrub, 1-2 m. Leaves 5-9.5 x 1-2.6 cm, elliptic, sometimes narrowly so; lower surface covered with a dense but loose continuous whitish to cinnamon indumentum composed of ramiform hairs, also with glandular setae overlying the midrib, epidermis glaucous-papillate; petioles densely tomentose, with some glandular setae. Flowers 4-5, in a dense truss; calyx 2-3 mm, coloured; corolla fleshy, crimson, tubular-campanulate, 35-40 mm; ovary densely rufous-tomentose and stalked-glandular, tapering into the glabrous style. Flowering April-May. Royal Horticultural Society (1997)

Distribution  Myanmar NE China NW Yunnan

Habitat 3,000-3,650 m

RHS Hardiness Rating H4

Conservation status Vulnerable (VU)

An evergreen shrub 3 to 9 ft high of stiff habit; young shoots clothed with loose and (at first) white wool and glandular bristles. Leaves lanceolate or narrowly elliptic, sharply pointed, 2 to 4 in. long, 12 to 114 in wide, dark green and becoming glabrous above, covered beneath with a thick loose wool which is at first dull white, later reddish brown, and persists till the leaf falls; stalk 14 to 12 in. long, woolly and glandular like the young shoot. Flowers in a terminal hemispherical truss 3 in. wide, opening in May. Calyx small, shallowly five-lobed, glandular; flower-stalk 58 in. long, woolly and glandular. Corolla bell-shaped, clear scarlet, about 112 in. long and wide, five-lobed. Stamens ten, 1 to 112 in. long, glabrous. Ovary slender, tapered, thickly clothed like the lower part of the style with glandular hairs. Bot. Mag., t. 9301. (s. and ss. Neriiflorum)

R. sperabile was discovered by Farrer and Cox in 1919, growing at 10,000 ft in a ravine below the Hpimaw pass in north-east Upper Burma and was introduced by them (Farrer 888); later sendings by Forrest were from the same area. According to the collectors’ field notes it varies in the colour of its flowers from scarlet-crimson to deep crimson, and also in habit, from compact to leggy, but is always comparatively dwarf, and this is also true of cultivated plants, which are normally less than 6 ft high.

R. sperabile is hardy in the woodland gardens of Sussex and flowers freely. It is not so fine a species as R. neriiflorum, but the dwarfest and most compact forms deserve to be propagated. It received an Award of Merit when shown by Lionel de Rothschild, Exbury, on May 5, 1925 (from Farrer 888).

A vigorous and tall-growing form of R. sperabile was introduced by Kingdon Ward in 1926 from the Di Chu valley on the borders between Assam, Tibet, and Burma (KW 7124).


R sperabilioides Tagg & Forr

Resembling the above in general appearance this differs in having no glands on the ovary, leaf-stalk, and young shoots. The stamens also are hairy at the base. Flowers of various shades of crimson, borne in trusses of six to ten flowers, the corolla 1 to 1{1/2} in long. A native of the Tsarong region of S.E. Tibet on the Salween-Kiuchiang divide; discovered by Forrest and introduced by him in 1921. It occurs at higher altitudes than R. sperabile – 12,000 to 13,000 ft – and is always of dwarf habit in cultivation, to about 4 ft high. It received an Award of Merit on April 4, 1933, when shown from Exbury.

var. sperabile

Leaf indumentum cinnamon when mature; leaves 2.5-3.5× as long as broad.

Awards AM 1925 (L. de Rothschild, Exbury) from Farrer 888; flowers scarlet.


var. weihsiense Tagg & Forr

Leaf indumentum whitish when mature; leaves 3-4(-8)x as long as broad. Royal Horticultural Society (1997)

Awards
AM 1985 (R.N.S. Clarke, Borde Hill) to a clone 'Rouge et Noir', from Kingdon-Ward 7124; trusses loose, up to 11 flowers, corolla deep crimson, with darker spotting in throat.

Taxonomic note This species is allied to R. sperabiloides (q.v.) and to R. floccigerum; from the latter it differs in its thicker, more persistent leaf indumentum. Royal Horticultural Society (1997)

Leaves relatively narrower, less lanceolate, sometimes elongate elliptic, with a paler and thinner indumentum. Introduced by Forrest from the Mekong-Salween divide west of Weihsi. It grows taller than the typical form and is of rather sparse habit. The name var. chimiliense was given to Forrest’s 26478, from the Chimi-li pass on the Nmai-Salween divide, but the name was apparently never published. In some of the cultivated plants from this batch of seed the leaves are almost glabrous beneath.

Feedback

A site produced by the International Dendrology Society.

For copyright and licence information, see the Licence page.

To contact the editors: info@treesandshrubsonline.org.