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 serotinum' from the website Trees and Shrubs Online (treesandshrubsonline.
Straggling shrub, to 3 m. Leaves 10–15 × 6–7 cm, oblong-elliptic, base unequally cordate, lower surface glabrous, with a glaucous papillate epidermis. Flowers 7–8, in a loose fragrant truss; calyx c.8 mm; corolla 7–8-lobed, white flushed pink, with a crimson blotch breaking into flecks within, open- to funnel-campanulate, nectar pouches lacking, 55–65 mm; ovary and entire style clothed with white stalked glands. Flowering July-September. Royal Horticultural Society (1997)
Distribution China S Yunnan Laos N Vietnam N
RHS Hardiness Rating H5
Awards AM 1925 (Royal Botanic Gardens, Kew); flowers white, flushed rose externally, blotched and tinged internally.
Conservation status Least concern (LC)
Taxonomic note This species was grown at Kew from seed thought to have originated in Southern Yunnan. It is allied to R. decorum but differs in the blotched corolla and in the habit of the plant. The occurrence of this species in the wild has now been confirmed by recent collections though it is still not clear as to how distinct it is from R. decorum. It is notable for its very late flowering period. Royal Horticultural Society (1997)
An evergreen shrub of loose straggling habit; young shoots and leaves glabrous. Leaves oval-oblong, rounded to shallowly cordate at the base, rounded and mucronate at the apex, 3 to 7 in. long, 11⁄4 to 23⁄4 in wide, dull green above, rather glaucous beneath; stalk 3⁄4 to 11⁄2 in. long. Truss composed of six to eight flowers which are fragrant. Calyx small, 1⁄3 in. wide, with shallow rounded lobes; flower-stalk slightly glandular, 1 to 13⁄4 in. long. Corolla 3 to 31⁄2 in. wide, funnel-shaped at the base, seven-lobed, the lobes spreading, notched in the middle, white flushed with rose and glandular outside, blotched and stained with red inside the funnel. Stamens fourteen to sixteen, of unequal length, their stalks white and downy at the base; anthers pale brown. Ovary and style glandular. Bot. Mag., t. 8841. (s. and ss. Fortunei)
This species was introduced to Kew in 1889 from the Jardin des Plantes, Paris, where it was raised by seeds collected by Delavay in Yunnan. It came as R. decorum and remained under that name until the true R. decorum of Wilson’s introduction flowered and showed the differences. The real R. decorum, as is now well known, is a sturdy, compact bush; R. serotinum is so lanky and so loth to branch that a plant was trained up a pillar at Kew as a sort of climber. The blotch at the base of the corolla and the reddish stains are further distinctions. Lastly it flowers in September, a fact which explains its specific name. Otherwise the two are very much alike in their blossom. It is quite hardy and gives a noble truss of blossom as the figure above quoted shows.