Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998
Article from Bean's Trees and Shrubs Hardy in the British Isles
'Rhododendron arborescens' from the website Trees and Shrubs Online (treesandshrubsonline.
Deciduous shrub or small tree, to 6 m; young twigs glabrous or (rarely) very sparsely covered with unicellular hairs. Leaves 4.5–8(–10.5) × 1.6–3 cm, ovate or obovate to elliptic, glabrous or nearly so. Flower bud scales with outer surface glabrous or with a few unicellular hairs, margin ciliate. Pedicels covered with gland-tipped hairs. Flowers with a cinnamon-like fragrance, appearing after leaf expansion, 3–7, in a shortened raceme; calyx 1–8 mm; corolla funnelform, tube gradually expanding into limb, white, outer surface covered with unicellular and multicellular gland-tipped hairs, 32–50 mm; filaments of stamens and style pink to red, contrasting with the corolla. Capsules covered with sparse unicellular and dense multicellular gland-tipped hairs. Flowering May-August. Royal Horticultural Society (1997).
Distribution United States E
Habitat 300–1,500 m
RHS Hardiness Rating H6
Awards AM 1952 (M. Adams-Acton, London) to a clone 'Ailsa'; flowers white, with yellow blotch.
Conservation status Least concern (LC)
Taxonomic note This species is closely allied to R. viscosum; the latter may be distinguished by its hairy young shoots and whitish filaments and style. Royal Horticultural Society (1997).
A deciduous shrub up to 20 ft high in the wild; young shoots glabrous. Leaves obovate or oval, pointed at both ends, 11⁄2 to 31⁄2 in. long, one-third to half as wide, glossy green and glabrous above except on the midrib, pale, glaucous, and glabrous beneath; margins edged with minute bristles. Flowers fragrant, 11⁄2 in. long, 2 to 21⁄2 in. wide, white tinged with pink; corolla-tube hairy-glandular, the lobes spreading; stamens five, bright red, much protruded; style still longer; flower-stalk 1⁄3 in. long, glabrous, or sometimes bristly. Calyx-lobes linear, 1⁄8 to 1⁄4 in. long, very bristly. (s. Azalea ss. Luteum)
Native of eastern N. America in mountainous regions; discovered by John Bartram, and introduced in 1818. This azalea, although now but little known, is one of the most beautiful of its kind, and is valuable in flowering late (June and July) when the plants have become leafy. It is allied to R. viscosum (whose flowers also expand after the young leaves), differing in its larger size, in the shining foliage, in the only slightly sticky corolla-tube and in its longer style and stamens. In drying, the foliage acquires a perfume like that of mown grass.
Award of Merit June 10, 1952, to a fine form with ten flowers to the truss, shown by Murray Adams-Acton (clone ‘Ailsa’).