Irises may be bulbous or rhizomatous. Bulbous Irises may sometimes have thick, fleshy roots. Bulbous Irise s include the Reticulate Irises which are dwarf, hardy bulbs that flower in the early spring, and the Juno and Xiphium Irises which include the brightly-coloured Dutch , English and Spanish irises . These thrive in any well drained soil in the full sun. These bulbs should be lifted in the autumn as they are not winter hardy.
Rhizomatous irises have sword-shaped leaves arranged in a basal fan.
For gardening purposes the main groups include Bearded, Crested and Beardless . Bearded Irises are characterized by a beard which runs along the centre of the falls. This group includes the common Irises and countless cultivars. Most flower during the late spring early summer. They are very suitable for herbaceous and mixed beds or borders.