is a genus consisting of 260-300 species of flowering plants in the family Iridaceae, native to Eurasia to Asia. Most species are found in temperate Northern hemisphere zones, and predominantly found in dry, semi-desert, or colder rocky mountainous areas, with some species growing in meadowlands, grassy slopes and riverbanks. Its name comes from the Greek word for rainbow, for it comes in many colours, though the signature colour of the iris is sky blue blotched with yellow. The name Iris is both the scientific or botanical name as well as the common name.
Irises are rhizomatous or bulbous, perennial plants. Some species grows from creeping rhizomes (rhizomatous irises) or, in drier climates, from bulbs (bulbous irises). The rhizomatous species usually have 3-10 basal sword-shaped leaves growing in dense clumps. The bulbous species have cylindrical, basal leaves.
The long, erect, inflorescences may be simple or branched, solid or hollow, and flattened or have a circular cross-section. The inflorescences contain one or more symmetrical six-lobed flowers which grow on a pedicel or peduncle. The three spreading or drooping downwards sepals are referrred to as 'falls'. These falls expand from their narrow base, which in some species has a 'beard', into a broader expanded portion known as 'limb'. The limb often adorned with veins, lines and dots. The three, sometimes reduced petals are upright, and stand partly behind the sepal bases. These petals are known as 'standards'.
Some smaller iris species have all the six lobes pointing upwards, but generally the limb and standards are differed in marked appearance. The lobes are united at their base into a floral tube that lies above the ovary, known as inferior ovary or epigynous. The styles divide towards the apex into petaloid branches, which are significant in pollination. The flower shape and the position of the pollen-receiving and stigmatic surfaces on the outer petals form a landing-stage for a flying insect.
Irises are popular garden plants with showy flowers, grown extensively as ornamental plants in home and botanical gardens. They are suitable for borders, containers and rock gardens. Japanese iris are often grown in moist sites and even standing water, such as lakes and bogs. Irises grow in any good free garden soil. The smaller and more delicate species needing only the aid of turf ingredients, either peat or loam, to keep it light and open in texture.
The most commonly found garden iris is Iris germanica
, the bearded German Iris and its numerous cultivars. They are easy to cultivate and propagate, and have become very popular in gardens. Bearded German irises are best planted as bare root plants in late summer, in a sunny open position with the rhizome visible on the surface of the soil and facing the sun. They should be divided in summer every two or three years, when the clumps become congested.
Rhizomes of the Sweet Iris (I. pallida
) and German Iris (I. germanica
) are traded as orris root. The roots are used in perfume and medicine, though more common in ancient times than today. Orris root are harvested, dried, and aged for up to 5 years. In this time, the fats and oils inside the roots undergo oxidation and degradation, which produces many fragrant and valuable compounds used in perfumery. The aged rhizomes are steam-distilled which produces a thick oily compound, known as "iris butter" or Orris Oil. The scent is said to be similar to violets.
Bearded iris grow from rhizomes, which produce off shoots that can be broken off and replanted. The most annoying pest for the iris is the Iris Borer. These are tiny caterpillars that chew their way down the leaf fold, eventually reaching the rhizomes. To elimiate the iris borer, destroy their eggs. Another problem affecting irises is soft rot, a bacterial infection. To get rid of soft rot, dig up the rhizome, cut away the infected areas, dry it, then dip in a solution containing 10-12% household bleach for a few minutes, rinse it with water and then replant.
Iris Germanica Hybrid
BS Thurner Hof