Rhododendron yedoense 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 yedoense' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-yedoense/). Accessed 2024-06-24.


Other taxa in genus


(var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.


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

Recommended citation
'Rhododendron yedoense' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-yedoense/). Accessed 2024-06-24.

Compact densely branched shrub, 1–2 m; young shoots covered with adpressed flattened bristles. Leaves of two kinds; spring leaves deciduous, 3–8 × 1–2.5 cm, elliptic-lanceolate to oblanceolate, apex acute, mucronate; both surfaces with scattered adpressed shining brown bristles, lower surface pale; summer leaves as for the spring leaves; petioles and pedicels covered with loosely adpressed bristles. Pedicel indumentum as for petioles. Flowers fragant; calyx 5–8 mm, lobes ovate; corolla rose to pale lilac-purple, with flecks, broadly funnel-shaped, 35–40 mm; ovary densely covered with adpressed hairs, style glabrous or pilose towards base. Flowering May. Royal Horticultural Society (1997)

Distribution  Japan Tsushima North KoreaSouth Korea

Habitat to c.1,100 m

RHS Hardiness Rating H5

Conservation status Data deficient (DD)

R.yedoense is the name given by Maximowicz in 1886 to a double-flowered garden form of an azalea that grows wild in Korea. Unfortunately this azalea was not described as a species until many years later and must therefore be treated as a variety of its own cultivated offspring:

var. poukhanense (Lévl.) Nakai

R. poukhanense Lévl.
R. coreanum Rehd

Flowers single; calyx 5–8 mm. Royal Horticultural Society (1997)

Taxonomic note This species is probably most closely allied to R. ripense, but it differs in the indumentum of the young shoots, etc. Royal Horticultural Society (1997)

A deciduous or nearly deciduous azalea 3, 4, or occasionally up to 6 ft high; young shoots clothed with appressed bristles. Leaves lanceolate, oval-lanceolate, or oblanceolate, pointed, tapered at the base to a stalk {1/8} to {1/6} in. long, 1{1/2} to 3 in. long; both surfaces bristly, especially at the margins. Flowers fragrant, produced in April and May usually two to four together in a terminal cluster; Flower-stalk {1/3} in. long, bristly. Calyx five-lobed; the lobes ovate, about {1/4} in. long, very bristly, especially on the margins, green. Corolla rosy purple, funnel-shaped, 1{1/2} in. long, rather more wide, five-lobed, freely spotted on the upper lobes. Stamens ten, about as long as the corolla, downy on the lower third; anthers purple. Ovary bristly; style 1{3/4} in. long, usually glabrous. Bot. Mag., n.s., t. 455 (s. Azalea ss. Obtusum)Native of Korea; introduced to the Arnold Arboretum by J. G. Jack in 1905, thence to England in 1913. It flowered at Kew in April 1914. Although now known by the above varietal name, it is a genuine wild type and according to Wilson is the common azalea of Korea from about the latitude of the capital, Seoul, southward, but is uncommon on Poukhan-san from which it derives its name. ‘It is partial to open country and on grassy mountain slopes and in thin Pine-woods it forms dense matlike masses from a few inches to a yard high … but in thickets the plants are more loosely branched and often two metres high’ (Monograph of Azaleas, p. 66). It also occurs on Daghelet Island (Quelpaert). It is perfectly hardy at Kew. The plant which provided the material figured in the Botanical Magazine is from a plant there raised from seeds collected in Korea by Mr Moorcraft in 1951, while serving with the British forces. The flowers in this form are rosy pink, but more commonly they are a vivid shade of lilac purple.R. yedoense var. poukhanense received an Award of Merit when shown by Capt. Collingwood Ingram, Benenden, Kent, on April 11, 1961 (flower-colour described as Mauve).The double-flowered type of the species is also known as ‘Yodogawa’, and was introduced to Europe from Japan in 1884.

var. yedoense

Flowers double; calyx to 15mm.

Only known in cultivation.