Temperate Asia - China, Japan, Korea
Climbers, semievergreen. Branches becoming hollow. Branches, petioles, and peduncles with dense, yellow-brown spreading stiff hairs, interspersed with long glandular hairs. Petiole 3-8 mm; leaf blade ovate or oblong to lanceolate, 3-8 × 1.5-4 cm, abaxially sparsely to densely hairy, adaxially hairy along veins, base rounded to subcordate, margin ciliate, occasionally sinuate, apex acute to acuminate. Flowers fragrant, paired and axillary toward apices of branchlets; peduncle 2-40 mm, shorter toward apex of branchlets; bracts leaflike, ovate to elliptic, 1-3 cm; bracteoles ca. 1 mm, pubescent, apex rounded or truncate and ciliate. Neighboring 2 ovaries free; ovary ca. 2 mm, glabrous. Calyx lobes triangular, ca. 1 mm, densely hairy abaxially and along margin, apex acute. Corolla bilabiate, white, becoming yellow, or purple outside and white inside, 3-5 cm, spreading hairy with interspersed long glandular hairs outside; tube 1.5-3 cm, not gibbous at base; upper lip irregularly 4-lobed, lobes 2-8 mm; lower lip recurved. Stamens and style glabrous, subequaling to exceeding corolla. Berries black when mature, glossy, globose, 6-7 mm in diam.; seeds brown, ovoid or ellipsoid, ca. 3 mm, shallowly pitted. Fl. Apr-Jun, fr. Oct-Nov. 2n = 18*.
Introduced in 1806 for ornament and later for erosion control; by 1919 naturalized from the Gulf of Mexico to Massachusetts.