Densely hairy shrub to c. 3 m high (sometimes taller in cultivation). Shoot quadrangular, tomentose; angles often with reddish hairs. Petioles short, tomentose. Lamina 4.5-11 × 2-5 cm, ovate to almost elliptic, villous on both sides, greenish white beneath, 5-veined; marginal hairs usually reddish (except in shade); apex acute. Bracts large, ovate, almost villous. Calyx c. 2 cm long, ± hispid with hairs often reddish; lobes 6-8 mm long, lanceolate. Petals 2.5-3.5 cm long, purple, obovate. Stamens very unequal; filaments mauve; anthers c. 1.5 cm long, slender and curved, purple, ± crimped. Style c. 3 cm long, shining crimson-mauve. Capsule 10-12 mm long, urceolate, hispid, with apex irregularly toothed.