Branched perennial, 30-60 cm. Leaves almost sessile, narrowly ovate or lanceolate, 3-7 x 0,5-3,5 cm, base cuneate or rounded, apex acute or acuminate, glabrous except for margin and midrib, pubescent when young, with numerous lateral veins. Inflorescence compact or loose, many-flowered. Calyx 2-3 mm. Corolla pale blue, glabrous outside, tube 10-12 mm, lobes 4-5,5 mm. Follicles 3,5-5 cm; seeds 6-8 mm, tuberculate. Fl. 5-6, In places wet during winter.
Introduced into W. European and American gardens as an ornamental plant for its profuse blue flowers, in cultivation it is more luxuriant, with looser inflorescences, than in the wild, where it is now very rare and near extinction.