A biennial or perennial herbaceous plant, reaching a height of 40 to 100 centimeters. The root is fusiform and often multi-headed. The stem is usually branched and almost bare or rough-haired. If it is hairy, then the hairs are mostly stalked-two-ray.
Numerous stem leaves are basal, ovate or lanceolate, sharp or long-pointed, toothed or almost whole, with simple coarse hairs or almost glabrous. Petioles become shorter from the base of the plant to the top.
Flowering from April to July with several inflorescences without bracts, reaching a diameter of 1.5-2.5 cm. Four sepals are elongated purple with a greenish tip, four corollas from 18 to 25 mm long with a narrow, long nail and an obovate plate. The flowers have a very strong but pleasant aroma in the late afternoon and at night.
The seeds ripen in pods 40 to 100 mm long and 1.5 to 2 mm wide.