In the open air this species can scarcely be regarded as a shrub. It is killed back to the ground most winters, but sends up vigorous, erect, woody shoots during the summer 3 to 6 ft high, bearing large heart-shaped leaves 4 to 8 in. long and nearly as wide, coarsely toothed, downy on the veins. In August and September come the terminal rounded corymbs, each 4 to 5 in. across, densely packed with purple-red blossoms. Bot. Mag., t. 4880.
Native of China; introduced by Fortune in 1844. It has lived for many years at the foot of a greenhouse wall at Kew, spreading rapidly by its suckers, and forming in summer a dense thicket of stems. It has proved hardy in an open position in the R.H.S. Garden, Wisley. Although the flowers are fragrant, the leaves when crushed emit a heavy nauseous odour. Easily increased by division in spring.