Rhododendron barbatum G. Don

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Credits

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

Recommended citation
'Rhododendron barbatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-barbatum/). Accessed 2024-10-10.

Genus

Rhododendron
Subsect. Barbata

Synonyms

Rhododendron lancifolium Hook, f., not Moench

Infraspecifics

Other taxa in genus

Glossary

calyx: (pl. calyces) Outer whorl of the perianth. Composed of several sepals.
corolla: The inner whorl of the perianth. Composed of free or united petals often showy.
included: (botanical) Contained within another part or organ.
ovary: Lowest part of the carpel containing the ovules; later developing into the fruit.
glabrous: Lacking hairs smooth. glabrescent Becoming hairless.
hybrid: Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
midrib: midveinCentral and principal vein in a leaf.
ovate: Egg-shaped; broadest towards the stem.
style: Generally an elongated structure arising from the ovary bearing the stigma at its tip.
viscid: Sticky.

References

Royal Horticultural Society (1997). The Rhododendron Handbook 1998

Credits

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

Recommended citation
'Rhododendron barbatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-barbatum/). Accessed 2024-10-10.

Rhododendron barbatum flowering at Cluny House Gardens, Perthshire, Scotland, 4th April 2021. Image Tom Christian.

Large shrub or small tree, 1.5–6 m; bark smooth and flaking, reddish brown; young shoots and petioles with long stiff bristles. Leaves 9–19 × 3.5–6.5 cm, elliptic to obovate, apex acute to acuminate, upper surface without strongly impressed veins, lower surface glabrous when mature or with scattered dendroid hairs and stalked glands. Flowers fleshy, 10–20, in a tight truss, crimson to blood-red, with darker nectar pouches (rarely pure white), tubular-campanulate, 30–35 mm; ovary densely stalked-glandular, also with some hairs, style glabrous. Flowering March-April. Royal Horticultural Society (1997)

Distribution S Tibet Bhutan India N Nepal

Habitat 2,700–3,700 m

RHS Hardiness Rating H5

Awards AM 1934 (C. Armytage Moore, Winterfield House, Cranleigh, Surrey); flowers Turkey Red.

Conservation status Vulnerable (VU)

Taxonomic note Closely allied to R. argipeplum (q.v.) but differing in the less hairy leaves. Royal Horticultural Society (1997)

An evergreen shrub or small tree, the bark peeling from the branches and leaving them blue-grey and smooth; winter-buds viscid; branches yellowish, sometimes glabrous, sometimes bristly. Leaves in a terminal cluster, oblong, heart-shaped at the base, terminated by a short, fine point, 4 to 9 in. long, 1 to 3 in. wide, dark dull green and ultimately glabrous above, pale and usually woolly at first beneath; stalk 1⁄2 to 1 in. long, conspicuously bristly on the upper side and at the base of the midrib. Flowers densely packed in a hemispherical truss about 4 in. wide, rich scarlet. Calyx with five glabrous ovate lobes, 1⁄4 in. long. Corolla bell-shaped, 11⁄2 in. across, five-lobed. Stamens ten. Ovary clad with long-stalked glands; style glabrous. (s. and ss. Barbatum)

Native of the Himalaya as far west as Kumaon, at 8,000 to 12,000 ft; introduced probably in 1829 (it was flowering in at least three gardens in 1848). This rhododendron is hardy in a sheltered spot at Kew, where it flowers in April. It is somewhat gaunt of habit, but worth growing for its marvellous richness of colour. It is, of course, much finer in Cornwall and similar places. There is some variation in the bristliness of the stems and leaves.

From the Supplement (Vol. V)

R. argipeplum – Included in R. smithii.

R. imberbe – Probably a natural hybrid between R. barbatum and R. arboreum (Rev. 2, p. 430).

Rhododendron barbatum in Ray Wood, Castle Howard, North Yorkshire, early April 2021. Image John Grimshaw.

Rhododendron barbatum planted by Reginald Farrer in the acidic soil of the Craven Fault where it slices through the limestone of the Ingleborough Estate, North Yorkshire (rather late flowering in May 2022). Image John Grimshaw.

The recumbent habit of an old Rhododendron barbatum in the Quarry Garden at Belsay Hall, Northumberland, UK, displays its colourful bark to advantage in May 2019. Image Owen Johnson.

R argipeplum Balf. f. & Cooper

This differs from R. smithii (see below) only in having a whiter and more persistent leaf-indumentum. It was described from specimens collected by Roland Cooper in Bhutan in 1915, and has also been found in Sikkim and in the Assam Himalaya. Cooper’s specimens were in fruit only, but in the Ludlow and Sherriff collections from Bhutan the flowers are described as bright rose or deep pink. For R. argipeplum at Glenarn see R.C.Y.B. 1968, p. 197.

R imberbe Hutch

This was described in 1928 from a plant at Kew of unknown origin, raised at the end of the last century. The differences from R. barbatum were given as: petioles and stems entirely without bristles, leaves relatively broader and shorter, calyx-lobes ciliate. It is matched by wild specimens from Kumaon, but is probably no more than a form of R. barbatum.

R smithii Hook.

Synonyms
R. barbatum var. smithii (Hook.) C.B. CI

Related to R. barbatum, but with the leaves clad beneath with a loose, greyish-white indumentum which becomes patchy by late summer. Native of the E. Himalaya. As seen in cultivation it is of more compact habit than R. barbatum, the leaves darker, with more impressed veins. Bot. Mag., t. 5120. It was introduced by Booth from just east of Bhutan and first flowered in 1859.It has been overlooked by botanists that the name R. smithii Hook. (1859) is illegitimate, being antedated by R. smithii Sweet (1831).

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