Rhododendron griersonianum Balf. f. & Forr.

TSO logo

Sponsor

Kindly sponsored by Peter Norris, enabling the use of The Rhododendron Handbook 1998

Credits

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

Recommended citation
'Rhododendron griersonianum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-griersonianum/). Accessed 2020-01-22.

Genus

Other species 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.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
bud
Immature shoot protected by scales that develops into leaves and/or flowers.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
fluted
Channelled or grooved.
glandular
Bearing glands.
inflorescence
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
lanceolate
Lance-shaped; broadest in middle tapering to point.
lax
Loose or open.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
ovate
Egg-shaped; broadest towards the stem.
relict species
Species that has survived unchanged from a previous age (a ‘living fossil’) or become geographically isolated from related species due to a change in circumstances.
section
(sect.) Subdivision of a genus.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.

References

There are currently no active references in this article.

Credits

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

Recommended citation
'Rhododendron griersonianum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-griersonianum/). Accessed 2020-01-22.

Shrub, 1.5-3 m. Leaves 10-20 x 2-5 cm, elliptic, apex acute to acuminate, lower surface covered with a dense whitish to pale brown lanate tomentum composed of dendroid hairs; petioles densely setulose-glandular. Flowers 5-12, in a lax truss; corolla deep rose to scarlet, tubular- to funnel-campanulate, 55-80 mm, outer surface of tube densely hairy; ovary densely covered with dendroid hairs. Flowering May-June. Royal Horticultural Society (1997)

Distribution  Myanmar NE China W Yunnan

Habitat 2,150-2,700 m

RHS Hardiness Rating H5

Awards FCC 1924 (T.H. Lowinsky, Sunninghill and L. de Rothschild, Exbury); flowers fiery salmon, with striking red filaments.

Conservation status Critically endangered (CR)

Taxonomic note A distinctive species that has been often used as a parent in garden hybrids. Royal Horticultural Society (1997)

An evergreen shrub of lax, open growth up to 7 ft or more high; young shoots glandular-bristly and hairy. Winter-buds very distinct, being encased by bracts extending well beyond the bud and free at the ends. Leaves oblong-lanceolate, pointed, tapered at the base, 4 to 7 in. long, 1 to 134 in. wide; dull green above, covered with a pale buff wool beneath; stalk 34 to 112 in. long, glandular and hairy like the young shoots. Flowers opening in June, loosely arranged in trusses of five to twelve flowers. Calyx small and like the flower stalk, which is 114 to 112 in. long, viscous and downy. Corolla rosy scarlet, trumpet-shaped, narrowed to a fluted cylindrical tube at the base, five-lobed, 3 in. wide, 212 in. long, the lobes roundish ovate, 114 in. wide, with darker crimson lines running into the throat, very downy outside especially towards the base. Stamens ten, crimson, 112 to 2 in. long, slightly downy on the lower half; anthers very dark brown. Ovary covered with pale tawny felt; style crimson, downy at the base. Bot. Mag., t. 9195. (s. Griersonianum)

R. griersonianum was discovered by Forrest in June 1917 in W. Yunnan, near the Burma border, on the divide between the Salween and the Shweli, a tributary of the Irrawaddy, growing at 9,000 ft in open situations. He introduced it in the same year and sent seeds again in later years, all from this area, to which the species is apparently confined. In his field notes for 1924 he wrote: ‘Extremely local; essentially a plant of the open, seldom, if ever, seen in the shade, though the glades where it is seen at its best are always more or less sheltered. In addition to the striking beauty of the flowers it is a most shapely shrub.’ (F.24280)

R. griersonianum is one of the finest and most remarkable of Forrest’s introductions. It was at first incongruously grouped with R. auriculatum, a species with which it really has nothing in common except the awl-shaped bud-scales. There it remained in the Auriculatum series, until 1964, when H. H. Davidian put matters right by placing R. griersonianum in a series of its own. It is taxonomically an isolated species, distinct from all others so far discovered in the combination of the awl-shaped bud-scales, the densely glandular inflorescence and ovary, and the uniquely coloured trumpet-shaped corolla. It is probably a relict species.

R. griersonianum is moderately hardy but needs the conditions suggested by Forrest’s field note, i.e., a sheltered but fairly sunny position. It flowered at Caerhays, Cornwall, and Borde Hill, Sussex, in 1923, and received a First Class Certificate when shown jointly by Lionel de Rothschild and T. H. Lowinsky at Chelsea on May 27, 1924. No other species of Rhododendron has been so much used in hybridising – the R.H.S. Handbook lists about 150 hybrids with R. griersonianum as one parent, and of these almost one-third have received an Award of Merit or a First Class Certificate. Many of these are described in the section on hybrids.


Feedback

A site produced by the International Dendrology Society.

For copyright and licence information, see the Licence page.

To contact the editors: info@treesandshrubsonline.org.