Stems 20-120 cm tall, usually glabrous, occasionally densely shorthaired, unbranched, rarely upper branched. Leaves all whorled, partially whorled to all alternate, sessile or with very short stalks, leaves ovate, ovate-elliptic to lanceolate, 2-7 cm long, 0.5-3.5 cm wide, base broadly cuneate to Round and blunt, acutely pointed, glabrous and green above, often glabrous and whitish below, sometimes with short hairs or nodular hairs on the veins, with fine serrations on the top edge.
Flowers solitary terminal, or several in a pseudoraceme, or inflorescence branched and integrated in panicle; calyx campanulate five lobes, white powder, lobes triangular, or narrowly triangular, sometimes toothed; corolla large, 1.5 long ~4.0 cm, blue, purple or white.
Capsule globose, or spherical obconical, or obovate, 1-2.5 cm long, about 1 cm in diameter. The flowering period is July to September.
Likes cool climates, hardy and sunshine. It should be cultivated in the hilly area below 1100m above sea level, in the sandy loam with half sun and half sun, and the neutral sandy soil rich in phosphorus and potassium fertilizers grows better. The seed life is 1 year, and storage at low temperature can prolong the seed life. Dry storage of seeds at 0~4℃ for 18 months can increase the germination rate by 3.5~4 times compared with normal temperature storage. The seed germination rate is 70%, and the temperature is 18~25 ℃, and there is enough temperature, and the seedlings emerge 15d after sowing.
