Butterfly Iris Dietes

Fortnight Lily is a rhizomatous evergreen perennial producing clumps of long, upright narrow leaves that reach 2 to 4 feet tall. The flowers rise above the foliage and look like small Japanese irises. Fortnight Lily produces many flowers from spring to late summer, with a fortnight (two weeks) of rest between each flowering period, thus the common name. It freely self-seeds, but you can prune the blossoms to reduce seed production.This plant looks amazing as a groundcover, in a potted container, or in a rock or woodland garden. It has grass-like features and dainty flowers that allow it to stand its own in any garden. Plus, it is low maintenance which can be a plus for any busy gardener. There are five species of Dietes, four from Africa and one species from Lord Howe Island east of Australia. The genus name comes from dis meaning double.

Best flowering occurs in full sun, but the plant does best with some part light afternoon shade. Fortnight Lily tolerates drought and some soil dryness, but you should provide regular moisture. The plant is winter hardy in USDA zones 9 through 11, but can be injured when temperatures drop below 50 degrees F. (10 degrees C). In cooler climates it can be grown as an annual or you can dig up the rhizomes and store them indoors for winter. Potted plants can be brought indoors. In the garden, the plants do best in moist, moderately fertile, well-drained soils in full sun to part shade. When planting, place the woody rhizomes 12 inches apart, 1 per square foot, and bury to a depth of 1 inch (2.5 cm). 

Diseases, Insect Pests, and Other Plant Problems:

Nematodes are the main pest problem. Scales can cover the foliage and cause a severe problem.