Plant 183

Iris species (Iridaceae)



The genus Iris comprises nearly 300 species, making it the largest genus of the family Iridaceae. They are perennial bulbous or rhizomatous plants distributed throughout Eurasia and North America, occupy a wide range of habitats from aquatic to semi-arid conditions and are found growing from sea level to high alpine altitudes.

The genus is aptly named after the Greek goddess of the rainbow, Iris. The diverse colour range found in the many species and hybrids almost covers the entire spectrum. However, individual floral displays are often rather fleeting. The vast array of colour is supported by a beautiful symmetrical floral arrangement. Each consists of six perianth segments or tepals (three outer 'falls' and three inner 'standards'), three fleshy style branches, three stamens and three fused carpels. In some forms the falls often exhibit a 'beard' or signal patch of varying colour to attract pollinators into the flower.

The genus has been valued for millennia. In 1400 BCE bearded irises were introduced from Syria to Egypt by Thutmose III, sixth Pharaoh of the Egyptian Eighteenth Dynasty, for his elaborate gardens. Dioscorides, the Greek physician, describes the medicinal properties of iris roots in book one of De Materia Medica, stating both Macedonian and Libyan species are 'suitable against coughs and reduce the intensity of thick mucus that is hard to get up' and 'cause sleep, provoke tears and heal suffering of the bowels'. The rhizomes of both Iris germanica and Iris pallida have been used in aromatic preparations, perfumery and aromatherapy treatments, producing a scent very similar to that of violets. The French King, Clovis I (c.466-511 AD), took the iris as his official emblem, following a lucky escape from rampaging Goths. The king was reputedly entrapped by the river Rhine, until a patch of yellow iris (Iris pseudacorus) revealed a safe fording point, enabling his army to flee impending attack.

Orris root, the dried roots of Iris germanica and Iris pallida, are also used in the preparation of Ras el hanout, a spice and herb mixture used extensively in Middle Eastern and North African cooking. Orris root is also one of the many botanicals used to flavour gin, providing not just a violet floral note but a 'woody sweetness' to the spirit. However, the production of orris root is lengthy. Once harvested the rhizomes are washed and then dried for three to four years before being milled to a fine powder.

Further reading

Mathew B. 1989. The Iris. Batsford.

Pavord A. 2009. Bulb. Mitchell Beazley.

Tom Price