Rhododendron orthocladum Balf. f. & Forr.

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

Recommended citation
'Rhododendron orthocladum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-orthocladum/). Accessed 2024-06-18.


Other taxa in genus


(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
The inner whorl of the perianth. Composed of free or united petals often showy.
Lowest part of the carpel containing the ovules; later developing into the fruit.
Lacking hairs smooth. glabrescent Becoming hairless.
Grey-blue often from superficial layer of wax (bloom).
Lance-shaped; broadest in middle tapering to point.
Egg-shaped; broadest towards the stem.
Generally an elongated structure arising from the ovary bearing the stigma at its tip.


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

Recommended citation
'Rhododendron orthocladum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-orthocladum/). Accessed 2024-06-18.

Much-branched erect low shrub, to 1.3 m. Leaves 0.8–1.6 × 0.3–0.6 cm, narrowly elliptic to lanceolate, apex obtuse, obscurely mucronate, lower surface covered with more or less touching yellow-brown scales, intermixed with few to many that are dark brown. Flowers (1–)2–5 per inflorescence; calyx 0.5–1.5 mm, lobes rounded to deltoid, unequal; corolla pale to deep lavender-blue to purple or whitish pink, funnel-shaped, 7–14 mm; stamens 8–10, shorter than to equalling corolla; ovary scaly, style short or long, glabrous or sparsely scaly. Flowering April-May. Royal Horticultural Society (1997)

Distribution  China N Yunnan, SW Sichuan

Habitat 2,500–4,500 m

RHS Hardiness Rating H5

Conservation status Least concern (LC)

An evergreen shrub of densely twiggy, bushy, shape, 3 to 4 ft high; young shoots very slender, densely scurfy. Leaves narrowly oblong or lanceolate, tapered at both ends; 13 to 34 in. long, 112 to 15 in. wide; dark slightly glaucous green and scaly above, furnished with glistening yellowish scales beneath, and sometimes with scattered larger brown ones; stalk to 34 in. long. Flowers two to four closely packed in terminal clusters 1 in. wide. Calyx minute, with small lobes covered thickly with glistening scales like the flower-stalk, which is only 112 in. long. Corolla pale mauve, 34 in. wide, with a very short, downy tube, five-lobed, the lobes rounded, ovate, 14 in. long. Stamens ten, purple, about 14 in. long, with a tuft of down near the base; anthers red. Ovary scaly; style glabrous, reddish, shorter than, or equalling, the stamens. (s. Lapponicum)

Native of N.W. Yunnan and S.W. Szechwan at alpine elevations, in open pastures, on stony slopes, cliffs, etc., sometimes on limestone; discovered and introduced by Forrest in 1913. This is a pleasing dwarf shrub with some resemblance to R. scintillans, but paler in colour of blossom than is usual in that species, and with a shorter style, which varies in length, but does not usually extend to the level of the anthers. There is also some variation in the density of the scales beneath the leaves; in some forms they almost conceal the surface of the blade, in others they are more widely spaced. It is quite hardy at Kew, grows well, and flowers freely towards the end of April, and is noticeable for its neat habit and rounded shape when young. Eventually it will reach a height of 4 ft, but remains of fairly dense habit; wild plants appear to be mostly quite dwarf.


Flowers pure white, about {3/4} in. wide, very freely borne. A small, dense shrub to about 2 ft high (R. microleucum Hutch.; R. orthocladum var. microleucum (Hutch.) Philipson & Philipson) Bot. Mag., n.s., t. 171A. ‘Microleucum’ was described in 1933 from a plant growing in Lionel de Rothschild’s collection at Exbury, which had almost certainly been raised from seeds gathered by Forrest in W. China. It is evidently an albino form, not a good species, and in the article accompanying the plate in the Botanical Magazine, Cowan and Davidian took the view that it is nearer to R. orthocladum than it is to R. scintillans, with which Hutchinson compared it. It is known only in cultivation, and no purple-flowered form has been found that matches it precisely in botanical characters. ‘Microleucum’ is one of the most attractive of the Lapponicums, and received a First Class Certificate when shown from Exbury in 1939.

var. longistylum Philipson & N.M.Philipson

Corolla blue or purple; style 15–16 mm. Royal Horticultural Society (1997)

Style longer than the stamens, as in R. scintillans, from which this variety can be distinguished by the much closer scales on the leaf-undersides. Introduced by Forrest (F.21988).

var. microleucum (Hutch.) Philipson & N.M.Philipson

R. microleucum Hutch.

Corolla white; style 3.5–5 mm. Only known in cultivation. Royal Horticultural Society (1997)

FCC 1939 (L. de Rothschild, Exbury); flowers white. AGM 1994

This is a variable species; var. microleucum may be no more than an albino form of var. orthocladum. Royal Horticultural Society (1997)

var. orthocladum

Corolla blue or purple; style 3.5–5 mm. Royal Horticultural Society (1997)