Proctor: Mystery shrouds history of cultivated iris

Published May 26, 2006 at midnight

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Irises were among the very first cultivated plants to be planted in Colorado soil. Settlers brought the rhizomes with them by covered wagon, along with shrub roses, lilacs and peonies. It's still possible to find sites of old homesteads on the plains, where these four pioneer plants have persisted for a century or more even though the cabins they once surrounded have nearly disappeared.

A friend gave me an old iris he found at one such site that turned out to be Iris flavescens, a pretty pale yellow species native to central Europe. Some scholars, however, think that this old iris may have been an ancient hybrid that escaped back into the wild. The history of cultivated iris reads like a mystery novel and there are many unanswered questions.

Most of us grow and love what we call "German bearded iris," and while there is a German connection, this is a group of plants that has swirled around Europe and the Middle East for a millennium. Species and early hybrids traveled with gardeners in the Ottoman Empire, crossed Europe with crusaders and were passed from monk to monk who processed the "orris" root.

Researchers have yet to unravel all the mysteries. The irises in your garden have a fascinating, murky past. With more than 200 species and thousands of hybrids, it would take a lifetime - and a very large garden - to grow all the irises in the world. Wild species are found throughout the northern hemisphere, from the blue flags we see in the Rocky Mountains and the yellow fleur de lis of France to the tiny snow iris from Turkey and the exotic water iris of Japan. These plants fill many niches in the garden. Some grow best in rock gardens or xeriscapes, while others prefer moist spots or standing water.

One of the parents of the colorful, beautiful hybrids we grow today is the old-fashioned Iris pallida. If you live in an older neighborhood, you may have a clump growing in the alley or perhaps beneath an ancient spirea bush. You can spot it by its plain lavender-blue flowers that smell like grape bubble gum. I didn't need to search the prairies for this species; mine came in an overcrowded clump growing by the front gate of my house. I divided that clump three years ago into a mind-boggling 100 pieces. I planted them throughout my garden in gentle, rolling curves among other tough perennials such as snow daisies and catmint.

They've plumped up nicely and promise a great, sweetly scented show in just a few days. They'll intermingle with the pale yellow I. flavescens and various rainbow-hued heirlooms passed down from my family. My garden has become a sanctuary for these beautiful, mysterious flowers. Many of these old hybrids and species may still survive in your neighborhood. Give them a prominent spot and grow them with pride and affection befitting their long, illustrious history.

Tips for the week

• Check for aphids on vulnerable plants such as columbines and roses.

• Begin regular fertilization of annuals, container plants and vegetables.

• Be vigilant about watering newly planted trees, shrubs and perennials throughout the season.

• Remove spent flowers of early-blooming perennials as they fade.

Rob Proctor's book, "First Garden: Getting Started in Rocky Mountain Gardening," is in bookstores.

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