Dietes bicolor

wild yellow iris


Dietes bicolor

(Steud.) Sweet ex Klatt 1866

pronounced: dy-AY-teez BY-kull-uh

(Iridaceae — the iris family)


common names: wild yellow iris, African iris, peacock flower

Dietes is from two Greek words, δις (dis), doubly, and ετης (etés) an associate, cousin, referring to the position of this genus between its two relatives Moraea and Iris; bicolor is Latin, having two colours.

This is a clumping, robust, grass-like rhizomatous perennial, a native of South Africa. It will form large clumps if left undisturbed for years, and, in doing so, offers good weed control. It is a very common plant in its native South Africa, where it is much used in places like public parks.

The leaves are long and sword-like, 1-2 cm in width, lime green in colour, with a double central vein, and grow from multiple fans radiating from the base of the clump. The plants usually grow to a height of 85-100 cm.

Flowers appear in spring and summer, produced at the ends of much-branched flower stalks. They are about 6 cm in diameter, flat, a pale creamy yellow, with three dark brown or purple spots, each spot surrounded by an orange ring. They last only for one day, but, because so many buds are produced, they appear to be always in flower during the flowering season. The flower is made up of 3 functional units, each consisting of an outer tepal and a style branch. Each unit must be entered separately by the pollinating insect (probably a bee). Nectar is secreted at the base of each of the outer tepals. When the pollinator pushes itself between the outer tepal and the style branch in its search for nectar, the pollen is deposited on its back, and as it proceeds from flower to flower the pollen is spread.

The flowers are followed by a club-shaped capsule, about 2.5 cm in diameter, which is quite heavy, and will often bend the stalk down to the ground. The capsule eventually browns and partially splits, dispersing dark brown seeds.

The plants prefer a dappled shade to full sun. They will grow in full sun, but will produce fewer flowers. Their ideal soil is fertile and well-drained, but kept moist.

Propagation is most easily done by lifting and division, although the plant can be grown from seed. It has been cultivated in parts of Europe since the early 1800s.

There is a miniature form of the plant, named ‘Mini Ballerina’.

The rhizomes of Dietes bicolor were traditionally worn as a charm to protect and strengthen the wearer.

It is interesting to note that members of the Dietes genus are found naturally only in South Africa, except for one species, D. robinsoniana, which is found on Lord Howe Island, near Tasmania. Of all the species, molecular analysis shows D. bicolor to be the most primitive, followed by D. robinsoniana, and it is therefore thought that the plants on Lord Howe Island must have originated from Africa; but how they reached Lord Howe Island is a mystery.


Photographed in Picnic Bay 2013
Page last updated 11th December 2018