An evergreen species varying in habit from a dwarf compact shrublet to a tall, straggly bush; young stems scaly, usually deep red, glabrous or slightly downy, never bristly. Leaves up to 2 in. long and 1 in. wide, oval, elliptic, oblong, or broadest slightly above or below the middle, usually rounded or obtuse at the apex, upper surface dull or glossy, with or without scales, underside glaucous and scaly, both sides glabrous or almost so; petiole very short. Flowers produced in April or May from axillary inflorescence-buds, which may be concentrated near the apex of the shoot or more widely spread along it; individual clusters with one to six flowers; pedicels up to 5⁄8 in. long. Calyx very small. Corolla widely funnel-shaped, pale to deep pink or rose-coloured, about 1 in. wide, the tube shorter than the lobes. Stamens ten, usually downy at the base. Ovary scaly; style usually longer than the stamens, glabrous, or downy at the base. Bot. Mag., t. 7301. (s. Scabrifolium)
Native of W. China, common in the drier parts of Yunnan, found at 9,000 to 14,000 ft in open places or as undergrowth in oak or pine woodland. It was first raised in the Jardin des Plantes, Paris, in 1889, and was introduced to Kew in November of that year. The seed had been gathered and sent to Paris by its discoverer, Père Delavay. R. racemosum soon spread into gardens and was awarded a First Class Certificate as early as 1892. But the present garden stock mainly derives from later sendings by Forrest, Kingdon Ward, and Rock.
R. racemosum is one of the most distinct and pretty of the dwarfer rhododendrons. Its most remarkable feature, which it shares with other members of the Scabrifolium series, is the production of flowers from the leaf-axils along the previous year's wood. Often from six to more than twelve inches of the shoot will be laden with blossom – very different from the single truss which in Rhododendron is usually seen terminating the shoot. On vigorous garden seedlings the season's growths are sometimes compound, consisting of the main shoot and several short laterals on which inflorescence-buds are developed. Another peculiarity of some garden plants is that a proportion of the inflorescence-buds abort and turn grey.
The flowers of R. racemosum vary much in depth of colour, but in a large group raised from seed – and few rhododendrons can be more easily or quickly raised by this means – the paler-coloured plants serve as a foil to those with flowers of a richer colour, and the total effect is delightful. But if there is room for only one or a few plants, a selection raised from cuttings is preferable.
A very dwarf and compact form of the species, with flowers of a deep cerise pink, was sent by Forrest in 1921 from the Sungkwei pass, Yunnan, under number F. 19404 – 'the finest form I have yet seen' he added in his field notes. The true form is available in commerce, but some plants sent out as R. racemosum F.19404 are evidently seedlings taken from open-pollinated plants, and are quite worthless.
cv. 'Glendoick'. – A tall-growing clone with deep pink flowers, distributed by Glendoick Gardens Ltd, Perth.
cv. 'Rock Rose'. – Flowers bright pink. Habit erect, to 4 or 5 ft. Award of Merit April 28, 1970, when shown by the Hydon Nurseries. The original plant was raised at Tower Court from Rock 59578.
There is also a white-flowered form in cultivation.
R. × pallescens Hutch. – The name R. pallescens was given by Hutchinson in 1933 to a plant at Exbury which arose as a stray from seeds under Rock's number 59574. It is a small, erect-branched shrub with oblong-lanceolate or oblanceolate leaves up to 3 in. long, glaucous and sparsely scaly beneath. Flowers with the characteristic shape of the Triflorum series but smaller, about 1 in. or slightly more wide, white, flushed with pink at the edges, produced from axillary as well as terminal buds and forming a dense cluster. Hutchinson suggested that the plant might be a natural hybrid between R. racemosum and R. davidsonianum, and Davidian, in his revision of the Triflorum series, confirms this identification. The original plant received an Award of Merit on May 2, 1933.
The rhododendron named R. fittianum by Balfour is without any doubt a natural hybrid of R. racemosum. It differs chiefly in its leaves, which are light green beneath and densely coated with pale yellowish uniform scales; and in the rosy-purple flowers more numerous in each truss and borne later. It is also stouter branched and the young stems are green. It was described in 1917 from a 'rogue' among seedlings of Forrest's 10278, sent home in 1913 and raised at Werrington Park, Cornwall, where Mr Fitt was head gardener. A peculiarity of this plant, according to Balfour, was that the flowers were borne at the ends of axillary shoots bearing a few leaves at the base. However, the plant was only four years old when described and as pointed out above it is quite usual in vigorous seedlings of R. racemosum for some of the axillary flower-buds to be replaced by short shoots ending in a flower-bud. These shoots may bear a few normal leaves at the base, but others, shorter, are furnished only with bract-like scales similar to those found at the base of any flower-bud of adult R. racemosum and are, in effect, stalked buds. Thus the fact that 'Fittianum', as it should be called, showed this peculiarity merely serves to emphasise its affinity with R. racemosum.
'Fittianum', in the herbarium, bears a superficial resemblance to R. dauricum var. sempervirens, which explains why R. fittianum Balf. f. appears as a synonym of R. dauricum in Species of Rhododendron.
A hybrid between R. racemosum and 'Fittianum', really a back-cross, has been named 'Fittra'.