Perennial or shrubby herb, usually glandular and sticky; stems up to 2 m tall, erect or rooting at base, glabrous to crisped-puberulous, sometimes also with long pilose hairs. Leaves with petiole up to 14(–17) cm long; lamina ovate-cordiform or broadly so, largest 11–28≈6–20 cm, apex acuminate, sometimes drawn out into a short obtuse tip, base cuneate to cordate, margin regularly to irregularly and sometimes grossly crenate-dentate (rarely subentire), glabrous to densely crisped-puberulous on veins, glabrous to sparsely puberulous on lamina. Panicle from very lax to narrow and contracted, (5–)10–45 cm long, finely puberulous and with usually dense broad glandular hairs, often also with long pilose hairs; primary bracts green to purplish, ovate to elliptic or obovate, from leaf-size to 10≈3 mm near apex, finely puberulous and with long pilose hairs, towards apex with stalked capitate glands; secondary bracts lanceolate to elliptic, 5–18≈2–5 mm; pedicels 0.5–7(–11) mm long. Calyx dark purple, with dense capitate glands, ± puberulous hairs and ± scattered pilose hairs; lobes linear-lanceolate, tapering gradually to distinctly spathulate, ventral and lateral (8–)12–19 mm long, dorsal (10–)14–21 mm long. Corolla pale to deep mauve, pale to deep purple or blue to dark blue with white throat, (25–)30–53 mm long, with purple to dark purple glandular hairs; tube 7–14 mm long; lower lip 20–38 mm long, lobes 2–5 mm long, ovate, subacute (lateral) or rounded. Filaments and style white; anthers black, (5–)6–9(–11) mm long, hairy along connective; staminodes filiform, 10–15 mm long, widened apically. Capsule (17–)20–35 mm long, the valves 2–3 mm wide, glandular-puberulous and usually with longer non-glandular hairs. Seed ± 1.5 mm long.