Description from Flora of China
Herbs perennial. Stems erect, woody at base, minutely white tomentose, much branched. Petiole 0-3 cm; leaf blade oblong to elliptic or ovate, 1-8 × 0.6-3.5 cm, papery, finely corrugate, minutely white tomentose, base rounded or subtruncate, margin crenulate, apex acute to mucronate, rarely acute. Verticillasters 2-18-flowered, in terminal racemes 4-18 cm; upper bracts broadly ovate, apex acuminate. Pedicel ca. 3 mm. Calyx campanulate, 1-1.1 cm in flower, dilated to 1.5 cm in fruit, minutely tomentose on veins and margin, sparsely golden yellow glandular, ± tinged purple, 2-lipped to ca. 1/2 its length; upper lip shallowly 3-toothed, teeth subulate; lower teeth triangular, apex acuminate. Corolla purple or blue, 1.8-1.9 cm, minutely tomentose; tube imperfectly pilose annulate inside, straight, ca. 9 mm; upper lip straight, obovoid, ca. 6 × 5.5 mm; lower lip ca. 1 × 1 cm. Filaments ca. 5 mm; connectives ca. 3 mm, arms equal. Nutlets dark brown, subglobose, ca. 2.5 mm in diam. Fl. Apr-Jun.
Cultivated in China as a medicinal and aromatic herb [Europe].