Now blooming: the magnificent irises.

Most often, you will see hybrid forms of the tall bearded irises. These plants are most popular among the 250 species of irises; hybridizers have been striving for decades to create imaginative new forms of the original plant, the German Iris (Iris germanica).

A comparison of the German Iris with any of today’s hybrids reveals a dramatic difference. The ancestor is an attractive but rather small, rather droopy flower on a short stem, with very few blossoms, usually an unexciting yellow or purple. The modern hybrid is much taller, with proud standards and horizontal falls, multiple stems and blossoms, and any of an astonishing range of colors—anything but true red—and combinations of colors.

The iris, named for the Greek goddess of the rainbow, has inspired legions of gardeners to collect and cultivate newly introduced hybrids and to share the rhizomes with friends (or customers). I have seen several private gardens with scores of different, striking tall bearded irises specimens, in a rainbow of colors, and a mere scattering of other plants. Only roses receive such dedication.

The popularity of the tall bearded iris can distract from other garden-worthy species in the genus iris. Indeed, at least 250 other species have been identified, each easily recognizable as an iris but with a unique look.

The principal groups of species irises are as follows:

Bulbous Irises

This group includes the Dutch, Spanish and English Irises (named most often for the country that popularized them, rather than the country of origin), and the Reticulata Irises (their bulbs have a reticulate or netted covering). Bulbous irises grow from bulbs, rather than from rhizomes.

Rhizomatous Irises

This group is most often hybridized, as already mentioned. The name refers to the colorful and fuzzy “beards” that decorate the falls. The beard serves no known function, but might attract pollinators.

There are two sub-groups of rhizomatous irises: bearded: dwarf, median, tall bearded, aril and arilbred (their seeds have an aril or “collar”); and beardless: Japanese, Louisiana, Pacific Coast, Siberian and Spuria irises.

Species Irises

There are many species irises, each with subtle differences. About eight are popular choices for home gardening. My garden includes an I. unguicularis, called the Winter Iris for when it produces light purple, fairly small blossoms, often hidden among an abundance of leaves. My specimen grew into a large clump, so yesterday I dug it out and used my dull garden hatchet to make four divisions of this Greek native for my Mediterranean Basin garden.

Crested Irises (botanically between bearded and beardless) and Tender Crested Irises (orchid-like blossoms; can be grown warmer spots of the Monterey Bay area).

More.

To learn more about irises…and especially options beyond the popular tall bearded irises…visit these websites:

• American Iris Society 
  Visit the “Iris Encyclopedia” for details on many species and hybrids. Also, see the page, “Resources and Iris Links” for local affiliates of this national organization, and “About Irises” for cultivation recommendations.
• Society for Pacific Coast Native Irises
  All about wild irises species that are native to the west coast.
• Species Iris Group of North America

An excellent (and fairly recent) book for a wealth of information is
Claire Austin’s Irises: A Gardener’s Encyclopedia (Timber Press, 2005).