Irises are extensively grown as ornamental plants in home, business, or botanical gardens. The Iris takes its name from the Greek word for rainbow, referring to the wide range of flower colors that are found among all the many species. Irises are grown from rhizomes (rhizomatous irises) or, from bulbs (bulbous irises). A rhizome is a plant stem that is usually found underground. Rhizomes are also referred to as creeping rootstalks or rootstocks. A bulb is a short stem with fleshy leaves or leaf bases.
Bulbs or rhizomes are dug and separated from larger clumps every two or three years to keep plants healthy and prevent crowding. Propagation of Iris is usually done about one or two months after the bloom season, usually in July or August. These dug and dried Iris bulbs or rhizomes are then available in the fall for planting or ordering.
However, now is the time to get out and observe the great variety of Irises available and find the color and size that you really like. Catalog pictures are nice but observation of the real thing tells you the whole story, size, color, scent, etc. Talk to your friends, neighbors, garden clubs, extension service and your local nursery staff. You may find bulbs available from growers that are digging iris to thin out their own gardens.
Staff Plant Physiologist