Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998
Article from Bean's Trees and Shrubs Hardy in the British Isles
'Rhododendron diphrocalyx' from the website Trees and Shrubs Online (treesandshrubsonline.
Shrub, 1-5 m; young shoots bristly. Leaves subcoriaceous, 9-14 x 3.5-5 cm, elliptic to obovate, apex apiculate, lower surface with a few bristles at base of midrib, otherwise glabrous. Flowers c.10, in a lax truss; calyx fleshy, red, 8-20 mm; corolla light to deep crimson, with poorly defined nectar pouches, funnel-campanulate, 30-40 mm; ovary densely rufous-tomentose, with a few stalked glands. Flowering April. Royal Horticultural Society (1997)
Distribution China W Yunnan
Habitat 3,000-3,350 m
RHS Hardiness Rating H5
Taxonomic note An anomalous member of Subsect. Glischra on account of its calyx and red corolla. It may have originated as a hybrid between R. habrotrichum and a species in Subsect. Neriiflora. Royal Horticultural Society (1997)
An evergreen shrub 5 to 15 ft high; young shoots and leaf-stalks clothed with a mixture of glandular bristles and short down. Leaves 21⁄2 to 6 in. long, 1 to 21⁄4 in. wide, elliptical to oblong, bright green above, pale and rather glaucous beneath, nearly or quite glabrous at maturity except on the midrib; stalk 1⁄2 to 3⁄4 in. long. Flowers opening in April and said to have as many as twenty flowers in a truss. Calyx very large, 1⁄2 to 3⁄4 in. long, unequally five-lobed, rather bell-shaped, bright red, but conspicuously spotted on one side. Corolla bell-shaped, 11⁄4 in. long, bright red to light rosy crimson with a crimson blotch at the base and crimson spots. Stamens ten, slightly downy at the base; ovary covered with tawny down as is also the base of the style. (s. Barbatum ss. Glischrum)
Native of W. Yunnan, China. It first appeared as a ‘rogue’ amongst R. habrotrichum in E. J. P. Magor’s garden at Lamellen in Cornwall, where it flowered in 1918. Sir Isaac Balfour appears first to have regarded it as a hybrid. Tagg, however, united with it the R. burriflorum described as a species by Balfour from a specimen collected by Forrest in W. Yunnan in 1918. It is remarkable for the size and colouring of its corolla-like calyx. A handsome rhododendron scarcely hardy enough to succeed at Kew.
Probably a natural hybrid of R. habrotrichum, with a member of subsect. Neriiflora as the other parent (Rev. 2, pp. 287-8).