Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
10/3/02
FOR IMMEDIATE RELEASE
Contacts:
Linda Naeve, Reiman Gardens, (515) 294-2710, lnaeve@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Reblooming Iris is No Fluke
By Linda Naeve
Extension Coordinator, Reiman Gardens
Do you remember the phrase, "You can't fool Mother Nature?" It was used in an old margarine advertising campaign. Maybe Mother Nature can't be fooled, but there are times when she is confused. I have seen rhododendrons and other spring flowering shrubs blooming sporadically in late summer. This week's Reiman's Pick, reblooming iris, might sound like a fluke or freak occurrence, but it's not. It's very natural and appropriate for this special type of iris variety to bloom again late in the season. Reblooming iris are known as remontant varieties. Tall bearded iris have their best bloom time in May, but will send up additional bloom stalks between August and October.
Tall bearded iris have been a fixture in Iowa gardens for years. Undoubtedly your grandmother and mother grew it in their gardens. Tall bearded iris add a blast of color to the garden in early summer. Varieties are available in every color of the rainbow, even black. In fact, Iris is Greek for rainbow. Unfortunately, the bloom time for typical tall bearded iris is only a couple weeks in early summer. After the flowers fade, the sword-like foliage takes up valuable space in the garden without contributing anything for the rest of the season. Reblooming iris enables gardeners to enjoy the beauty of iris for more than just a couple weeks.
Reblooming iris seem to be a well-kept secret even though there are nearly 700 varieties on the market, 200 that are hardy in zone 5. They are not a recent development, either. In 1967, the Reblooming Iris Society was formed as a section of the American Iris Society. Today its 600 members are devoted to promoting interest and development of all iris types having more than one bloom season per year.
Reblooming iris tend to be more vigorous and often bloom a week or so earlier in the spring than standard bearded iris. An iris botany lesson will help you understand why some varieties rebloom. Bearded iris grow and spread by rhizomes, or fleshy underground stems. At the end of a young rhizome segment is a fan of leaves. The buds for next year's flowers are formed deep in this fan in late summer. The flower stalk emerges from that fan of leaves the following spring. Rebloomers, however, complete their growth cycle in a single season enabling them to bloom again in the fall.
The best time to divide and plant iris rhizomes is in late summer so they have time to develop adequate root growth and become established before winter. Planting iris is a bit different than planting other perennials. The rhizome should be planted just below the soil surface. Plant them in a triangle with a rhizome at each corner. Space them least 18 inches apart with the "toes," or cut end, pointing toward the center and the leaf fans on the outside.
Once growing in the garden, iris are low maintenance. However, since rebloomers grow and flower faster than the standard types, they need additional fertilizer and water. Apply a complete analysis fertilizer, such as a 10-10-10, in spring and again in summer at a rate of one-quarter pound per 25 square feet.
There are many good reblooming iris varieties on the market today in a wide range of colors. You can find a list of sources for reblooming iris rhizomes on the Web site for the Reblooming Iris Society at www.rebloomingiris.org. When selecting which iris variety to plant in your garden, be sure to choose those that are hardy and reliably rebloom in your zone. 'Immortality' is a popular, reliable rebloomer that is hardy as far north as zone 3. It has large, pure-white blossoms and is a real eye catcher in the spring and even more so in September. Every year, members of the American Iris Society rank their 100 most popular iris varieties. For the past three years, 'Immortality' has ranked in the top 30.
While most other plants are fading and getting ready for winter, you will find 'Immortality' iris blooming beautifully in the Town and Country Garden at Reiman Gardens.
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