Deciduous shrub, to 2 m. Leaves 4-18 x 1.5-8.5 cm, obovate, often broadly so, to broadly elliptic, lower surface with scattered eglandular and gland-tipped hairs, the midrib fringed with straight to crisped unicellular hairs. Flowers appearing with or after the leaves, 6-15, in an umbellate raceme; calyx 1-6 mm; corolla white, lacking spots, regular, tubular-campanulate, tube broadly expanding into the shorter limb, 15-25 mm. Capsule covered with gland-tipped hairs. Flowering May-June. Royal Horticultural Society (1997)
Distribution Japan S
Habitat 1,000-1,850 m
RHS Hardiness Rating H6
Conservation status Least concern (LC)
Taxonomic note This is a very distinctive species on account of its regular tubular-campanulate flowers. It may be distantly allied to R. albiflorum. It is considered to be one of the most primitive species in the genus. Royal Horticultural Society (1997)
A deciduous azalea described as of bushy habit and from 3 to 6 ft high; the stiff young shoots reddish brown and clothed with glandular bristles. Leaves scarcely stalked, obovate, rounded, and often notched at the apex, tapered to the base, 2 to 6 in. long, half as much wide, more or less appressed-bristly above and beneath. Flowers opening about midsummer, six to fifteen in a cluster, the pedicels 1⁄2 to 3⁄4 in. long, sticky with glands. Calyx small, with five ovate, ciliate lobes. Corolla narrowly bell-shaped, scarcely 1 in. long, white with five short, slightly spreading lobes. Stamens ten, unequal in length but all shorter than the corolla, downy below the middle. Ovary glandular-hairy; style glabrous. Bot. Mag., n.s., t. 491. (s. Azalea ss. Nipponicum)
Native of the mountains of Central Japan, where it occurs only in a few localities; discovered in 1883. Its existence in gardens is apparently due to E. H. Wilson, who found it on the hills around Toge in 1914 and sent seeds to the Arnold Arboretum. It first flowered at Kew in June 1921, but this species is no longer there. The blossom is very disappointing, being small and hidden away in the young growths. But in foliage it is one of the finest of azaleas and it takes on brilliant orange and crimson tints in autumn. The bright reddish-brown bark is also pleasing. Botanically it is distinct in having the stamens and style included within the somewhat tubular corolla, which resembles that of Menziesia ciliicalyx in shape.