Each species has ribbed leaves in a cluster at the base of the plant and tubular white or bluish purple flowers that are borne in clusters at the tip of stalks that emerge from the leaves. Bloom time varies from late spring to early fall depending on the species. The fruit is a long capsule. The ornamental plants are frequently grown for their conspicuous foliage, which may be light-to-dark green, yellow, blue, or variegated. The leaves are generally large but range in size from 1.2 to 45 cm (0.5 to 18 inches) long and 1.2 to 30 cm wide.