People who appreciate the stately majesty of tall bearded irises in their gardens can now enjoy these flowers for more than their usual two- or three-week spring bloom.
Hybridizers have been hard at work developing re-blooming (remontant) bearded irises, particularly tall bearded (TBs), and the result is that Orange County gardeners can select from among hundreds of varieties that will bloom up to four times during the year.
Gene Strawn, president of the Orange County Iris and Daylily Club, grows more than 200 TBs in his garden.
"They're so much less trouble to grow than most flowers," he said.
The re-blooming factor, a genetic trait, is not new in irises, but because the flower size and quality had been less visually dramatic than once-bloomers, hybridizers had concentrated on once-bloomers with their ruffles and other glamorous characteristics.
However, there were a small number of hybridizers who pursued the quest of irises that would flower more than once during the year, even if their flowers weren't as spectacular. Iris fanciers have responded so strongly to their efforts that re-blooming irises are now responsible for the surging popularity of this perennial.
Median and dwarf bearded irises also re-bloom, but the TBs are the most popular.
"People mostly want tall bearded iris," said Nancy Holk, who with her husband, Herb, owns and operates Cal-Dixie Iris Gardens in Riverside. "We grow 2,500 different varieties because we enjoy them so much," she added. "Iris add so much color to a garden because they come in practically every color except red and grass green.
"I can pick an iris every day of the year," Holk added.
Re-bloomers perform especially well in Southern California with its long growing season. But to ensure that the plants live up to their genetic potential, it's essential that they receive proper care.
"Although people tend to regard iris as drought tolerant, in fact they must receive regular, adequate water to ensure that they will re-bloom," said Garden Grove resident Nancy Webb, regional vice president for the Iris and Daylily Society.
Webb waters her 100 irises once weekly during the hot summer months. Irises also need regular fertilizing to ensure that they will re-bloom.
Webb recommends the following feeding program: feed at the end of February; early spring; late spring, and early fall. She uses a foliar feed such as Miracle-Gro plus granular rose food scattered at the base of the plant.
"The ideal feeding program is to feed one-quarter of the recommended strength every time you water them," she added.
Irises will grow in any good garden soil. They can grow and bloom well with a half day of sun but prefer full sun. But they don't like their feet wet--the soil must drain well so their roots don't sit in water.
The best time to plant iris rhizomes is July through August, so now is the time to plan and order the ones you'd like to add to your garden.
"Re-blooming and other irises are really best bought through catalogue sources or obtained from specialty growers or even local iris clubs," Webb said. "Those sold in most nurseries usually aren't identified by specific name, and their selection is limited."
Prices of rhizomes range from $2 to $25 for the rare varieties.
Plant single rhizomes in soil that has been well-worked with added compost. At the time of planting, a balanced fertilizer (numbers the same such as 10--10--10 rather than one high in nitrogen) can be worked into the soil.
Place rhizomes 12 to 18 inches apart. Dig a shallow hole large enough to fit any roots on the rhizome, and make a cone in the center of the hole. Place the rhizome on the cone and spread the roots evenly down the cone's sides. The top of the planted rhizome should be just half an inch below the level of the surrounding soil if the soil contains a lot of clay, and 2 inches below soil level in sandy soil.
Fill the hole with soil, press firmly in place and water well. Keep the soil moist, but not wet, during the growing and blooming season.
Irises can be attacked by aphids. Any spray recommended for roses and other ornamental flowers can be used on irises.
After several years, the iris clumps may be crowded and will need to be divided because crowding diminishes bloom. Some varieties of re-blooming irises grow more quickly and may require dividing yearly.
Dig up the clump, discard the old, spent rhizomes, and save only the large new fans with foliage. Iris growers recommend replanting them in ground where irises have not been grown recently. If that's not possible in your garden, be sure to add liberal quantities of compost to replace the soil micronutrients already used by the irises.
Re-blooming irises do not all repeat in the same patterns. Some bloom again in the fall; others will bloom regularly throughout the year.
For advice in selecting and growing irises, contact the Orange County Iris and Daylily Club. Meetings are open to the public and free at 7:30 p.m. the second Tuesday of each month at the First Presbyterian Church of Garden Grove, 11832 Euclid St.
There is also a national organization exclusively devoted to re-blooming irises. The Reblooming Iris Society publishes an informative newsletter, the Reblooming Iris Recorder. Membership is $4 a year for an individual; $5 for a family. Contact Howard Brookins, N75W14257 N. Point Drive; Menomonee Falls, Wis. 53051.