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').
var. richardsonii Rehd. – A variety of the higher mountains at 3,800 to 5,200 ft, usually not much over 4 ft tall, and with somewhat smaller and more glaucous leaves.