African Iris, Dietes vegeta, This is a clumping, robust perennial that has stiff leaves radiating up and out in a fan-shaped pattern. The flower spikes are topped with 3-inch white flowers marked with yellow and blue. Although short-lived (about 2 days), the flowers are produced sporadically throughout the year, especially in spring and early summer. They can grow to 24 to 30 inches in height and wider in spread. African Iris should be planted in well drained soil and full to nearly full sun.