Family: Iridaceae

Of the six species of this genus of evergreen, rhizomatous perennials, five originate from tropical and South Africa, and one from Lord Howe Island, Australia. In warm weather, when in flower, they have very pretty, iris-like blooms. The stiff, sword-shaped foliage also makes them good landscaping subjects. In frosty climates, grow these perennials in a cool greenhouse.

Species

D. bicolor grows to 1 m (3 ft), with sword-like, mid-green foliage. Sprays of flat­tened, threepetalled, pale yellow flowers, with a conspicuous, brownish black, basal spot, appear in summer on wiry stems. Healthy plants will flower almost continuously.

D. grandiflora, wild iris, to 1 m (3 ft), has sim­ilar foliage, but the flowers are larger, in white, marked with yellowish orange, brown and blue-mauve.

D. robinsoniana, wedding iris, from Lord Howe Island, has richly fragrant, white flowers, 10 cm (4 in) across, with red and yellow spots near the base. The leaves and stems are up to 2 m (6 ft) tall.

Cultivation

These drought-tolerant plants will grow in any well-drained, average soil in full sun. They can do well in partial shade, though flowering may be poorer. Once established, they self-seed, and clumps can be divided when overcrowded. Under glass, grow in soil-based potting compost with good light and ventilation.

Climate

At least zone 9.