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 flammeum' from the website Trees and Shrubs Online (treesandshrubsonline.
Deciduous shrub, to 2.5 m; young twigs densely covered with eglandular hairs. Leaves (3-)3.9-6.3(-8.2) x 1.5-2.4(-2.7) cm, ovate or obovate to elliptic, lower surface densely eglandular-hairy or glabrous. Flower bud scales with outer surface covered with unicellular hairs, rarely glabrous. Flowers with an acrid fragrance, appearing before or with the leaves, 6-11, in a shortened raceme; calyx 1-3(-5) mm; corolla scarlet to orange, funnelform, tube abruptly expanding into the limb, outer surface of corolla covered with eglandular hairs, 27-45 mm. Capsule with eglandular-hairs. Flowering April. Royal Horticultural Society (1997)
Distribution United States SE
Habitat s.l.-500 m
RHS Hardiness Rating H5
Conservation status Vulnerable (VU)
Taxonomic note R. flammeum differs from the allied R. prunifolium and R. cumberlandense in the precocious flowers that appear before the leaves. Royal Horticultural Society (1997)
A deciduous azalea up to 6 ft high; young shoots finely downy and bristly. Leaves obovate, oval, or oblong, 11⁄2 to 21⁄2 in. long, half as much wide; upper surface bristly, lower one finely downy with bristles on the midrib; margins bristly; stalk 1⁄6 in. long. Flowers opening in April and May, up to as many as fifteen in a truss. Corolla funnel-shaped, about 13⁄4 in. long, the tube slender, cylindric, and downy outside; scarlet or bright red with an orange-coloured blotch on the upper lobe. Stamens five, 2 in. long, downy below the middle. Ovary clothed with bristly, not glandular hairs; style 2 in. or more long, downy at the base. Calyx with five very small, ciliate, ovate, or oblong lobes. Flower-stalks bristly. (s. Azalea ss. Luteum)
Native of the S.E. United States from Georgia to S. Carolina. This, the most brilliantly coloured of all American azaleas, was in cultivation as long ago as 1789, and was figured in the Botanical Magazine in 1792 (t. 180). Old plants may still be in gardens, but the name appears to have been lost. It was in cultivation at Kew in 1881 as ‘Azalea nudiflora coccinea’. Plants were sent to England by Professor Sargent in 1916. It has been confused with R. calendulaceum, but differs in the slender corolla-tubé which is not glandular as it is in that species. The flowers also are more numerous in the truss, and the colour ‘is always scarlet or bright red and never varies to yellow’ (Rehder). R. calendulaceum is a more northern shrub and hardier, but, as may be gathered from what is stated above, R. flammeum is quite hardy in this country. No doubt many of our richest- coloured deciduous azaleas owe much of their vivid red and scarlet hues to this species.