Rhododendron weyrichii Maxim.

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Peter Norris, enabling the use of The Rhododendron Handbook 1998


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

Recommended citation
'Rhododendron weyrichii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-weyrichii/). Accessed 2024-07-17.



  • Rhododendron shikokianum Makino

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.
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
Egg-shaped; broadest towards the stem.
Generally an elongated structure arising from the ovary bearing the stigma at its tip.
Arrangement of three or more organs (leaves flowers) around a central axis. whorled Arranged in a whorl.


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

Recommended citation
'Rhododendron weyrichii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-weyrichii/). Accessed 2024-07-17.

Shrub or small tree; young shoots soon becoming glabrous. Leaves in whorls of up to three, at the ends of the branches, 3.5–8 × 1.5–6 cm, broadly rhombic, apex acute, lower surface with scattered brown hairs, especially on the midrib; petioles covered with brown pilose hairs at first, soon glabrescent. Pedicels densely covered with brown pilose hairs. Flowers 2–4 per inflorescence, appearing before or with the leaves; calyx minute; corolla pink to brick-red, with darker flecks on upper lobes, open-funnel-campanulate, 30–40 mm; stamens 10; ovary densely pilose, style glabrous or pilose below, sometimes also papillate. Flowering April-May. Royal Horticultural Society (1997)

Distribution  Japan Kyushu, Shikoku, SE Honshu North KoreaSouth Korea

Habitat 20–1,200 m

RHS Hardiness Rating H4

Conservation status Least concern (LC)

Taxonomic note R. weyrichii may be distinguished from the allied R. sanctum and R. amagianum by the larger flowers, to 40mm long, and the more numerous flowers per inflorescence. Royal Horticultural Society (1997)

A deciduous azalea, described as often tree-like in habit in the wild, 3 to 15 ft high (Wilson); young shoots clothed with forward-pointing hairs, becoming brown and nearly glabrous the second year. Leaves obovate, ovate, or diamond-shaped, usually acutely pointed; distributed along vigorous shoots but often produced in a whorl at the end of shorter twigs, 112 to 312 in. long, 1 to 214 in. wide, pale green and soon glabrous above, greyer green and rather conspicuously veined beneath; stalk 14 to 12 in. long, downy only when young. Flowers produced two to four together in a terminal cluster. Calyx very small, hairy. Corolla about 2 in. wide, of a rather dull rich red, funnel-shaped at the base, with five spreading lobes. Stamens six to ten, usually glabrous. Ovary densely clothed with erect, pale, reddish hairs; style usually glabrous. Bot. Mag., t. 9475. (s. Azalea ss. Schlippenbachii)

Native of S. Japan, in Kyushu, Shikoku, and the Kinki district of the main island; also of the Korean island of Quelpaert; introduced by Wilson in 1914 to the Arnold Arboretum. Plants raised from seed obtained from that institution in 1915 flowered in May 1921 at Kew, where the species has proved fairly hardy in a sheltered place. It is most nearly akin to R. reticulatum, but is well marked by the colour of the flowers which may be termed rich brick-red and as distinct among azaleas as that of R. griersonianum is among rhododendrons proper.

R amagianum (Makino) Makino ex Nemoto

Azalea amagiana Makino

Closely related to R. weyrichii, but with thicker leaves, lustrous above, the base of the midrib beneath and the petiole white-tomentose; they are commonly rhombic in outline and relatively rather broader than in R. weyrichii. The flowers are often more than 2 in. wide and are borne in July after the leaves have expanded. Bot. Mag., n.s., t. 379. It is a local species, confined to Mt Amagi and Mt Hijane in Idzu province; introduced to Britain in the late 1930s. It is hardy but needs light shade at least in southern England. A mature specimen of this azalea is a wonderful sight when in flower. The colour is a soft shade of true scarlet, with darker spotting on the upper lobe. Award of Merit July 6, 1948, when shown by Lord Aberconway, Bodnant.

R sanctum Nakai

This, another native of Japan, is very closely allied to R. amagianum, but the flowers are rose-coloured and are borne earlier, in May or June. Like R. amagianum it is a local species, found wild only in the mountains south-east and south-west of Nagoya.