Annuals, biennials and perennials, some with tap or fibrous roots and a few with rhizomes or runners. Upright or decumbent stems bearing lance-shaped, entire or toothed stem leaves and occasionally rosettes of slightly larger ones. Grown for their mostly fragrant, saucer- or trumpet-shaped, bright white, yellow or pink flowers produced over a long period during summer. Best in full sun and well-drained soil. Useful in borders or rock gardens.