Iris afghanica 

Occurs only in north-east Afghanistan.

Iris afghanica is a striking species. The slender, bluish-green leaves can be up to 30 cm long, though are often shorter, and the outer ones are sickle-shaped.

All irises have six perianth (sepals and petals) segments making up the flower. Three arch downwards and are called ‘falls’, and three point upwards and are called ‘standards’. The flowers of I. afghanica are about 8–9 cm across. The pointed creamy-white falls are heavily veined with purple-brown and have a solid purple patch in the centre. Each fall has a beard of yellowish or purple hairs at its centre. The pointed standards are pale yellow and have a beard of greenish hairs on the lower part.

At higher altitudes the plants are more strongly coloured and only about 10 cm tall. At lower altitudes the flowers are larger and more softly coloured, and the plants can reach 25 or 30 cm tall.

Although far from common, Iris afghanica is now established in cultivation.

In its natural habitat, Iris afghanica experiences hot, dry summers and freezing winters so it is perfectly hardy but must be kept dry when dormant. For this reason it is best grown in a well-ventilated cold frame or alpine house, to protect the rhizomes from rain in the summer.

Regelia irises often do better if given a free root-run by planting directly into a frame bed. Some species, such as I. hoogiana from the Pamir Alai in Central Asia and I. korolkowii from the Tien Shan and Pamir Alai mountains of Central Asia, can be grown outside in a well-drained, sunny border. Plants can be increased by dividing the rhizomes in late summer, as the plants are re-potted.

Iris afghanica is rare in cultivation and it is even rarer to find two clones grown together, so seed is very seldom available. Different clones are needed because the plants are self-incompatible, so a flower cannot be fertilised by its own pollen.

Iris afghanica can be seen in the Alpine House at Kew when in flower.

Spirit-preserved specimens of Iris afghanica are held in Kew’s Herbarium, where they are made available to researchers, by appointment. The details of one of these specimens can be seen on-line in the Herbarium Catalogue.

Search Kew’s science databases for more information on this species

Visit Kew’s Davies Alpine House

Read the Alpine & Rock Garden Team blog

Buy 'Alpines from Mountain to Garden' by Richard Wilford

Curtis’s Botanical Magazine (Wiley-Blackwell)