This is a very useful and adaptable rhizomatous perennial. I don't advocate the growing of the green-leaved Dietes iridoides or Dietes grandiflora (which may in fact be the same plant?), which self-seed prolifically and are rather weedy, but this lovely cultivar has creamy-white stripes on the long, thin leaves. It grows in an upright clump to about 60 cm tall and will grow in sun or shade. It has the same iris-like white flowers Dietes grandiflora, which appear sporadically from spring to autumn, but it has never self-seeded in my garden. It is quite drought tolerant once established. It mixes well with silvery-leaved plants and white-flowered specimens, to echo its leaf markings. It can be grown in a container. Remove the seed pods and occasionally groom the plant of scruffy leaves. It is said to be frost tolerant and suitable for seaside gardens.
Note that parts of this plant are poisonous if ingested. It can also cause skin irritation in some people.