Irises are a springtime garden favorite throughout the South, especially because the older traditional types are dependable perennials that make few demands. And now many bloom more than once.

Margie Lee is a local gardener who sought more information on the reblooming bearded iris that can add to fall gardens.

The Reblooming Iris Society says the variety has been around for 50-plus years, and more than 2,500 irises rebloom in zones 6, 7, 8 and 9. They range from whites and yellows to pinks, blues and purples. Some are picatas, blooms delicately edged with a contrasting color and bi-colors that have standards or upright petals of one color or shade and falls of another.

Their cultivation is similar to the regular bearded iris with a few distinctions. Because of these distinctions, the society recommends they not be planted in the same bed. The rebloomers take more care, more fertilizer and more water, and they are not allowed to go into the dormant stage the spring flowers have. They multiply quickly and need to be separated every third year to keep the clump vigorous.

The society’s website, www.rebloomingiris.com, suggests planting the flower in raised beds with careful soil preparation.

Initially, the soil should be dug out of the planting site to a depth of at least 8 inches and set aside. In a wheelbarrow, one part concrete sand and two parts compost in a quantity that will fill the wheelbarrow should be mixed with 1 cup each of rock phosphate, green sand, granular dolomite (calcium and magnesium), wood ashes and a good, balanced slow-release fertilizer with micronutrients.

The mixture should then be combined at a ratio of 1:2 to the soil that was removed from the planting bed. Some growers prefer alfalfa pellets or meal as their slow- release fertilizer. When the soil is well mixed with the sand/compost mixture, the rhizomes can be planted with the fans facing out. The best method is to create a mound of soil so the rhizome can be set on the mound and the roots can be spread out around the rhizome. The roots should be covered with soil; however, a small portion of the rhizome should remain above the soil and watered in deeply, but not mulched. Mulch can lead to rot and other iris diseases, as well as serve as a hiding place for iris borers. Good drainage, full sun and a neutral pH are recommended.

Fertilization criteria is different for the rebloomers.

The Society recommends fertilizing them in early spring with 5-10-5 mixed with super phosphate, 0-45-0, around the root zone but never directly on the rhizome with a re-application immediately after blooming. Two applications of a liquid fertilizer in September will enhance fall blooming. They need watering at least every other week if rain is unavailable during the hot summer months to inhibit dormancy and allow the fall blooms to form. The fall blooming cycle is generally set off by cooler night temperatures.

For the best display, plant three to seven rhizomes of the same variety together, 12-18 inches apart for the tall-w growing varieties and closer for the small and dwarf varieties. Interplant them with other perennials, particularly members of the daisy and mint families, to help curb outbreaks of iris pests. Immortality, with its pure white blooms, is one of the most popular and dependable rebloomers.

Gardeners should dig and divide reblooming clumps in mid- to late summer. The clumps should be dug with lots of soil attached and only half of the clump divided at a time. The rest of the clump should be replanted immediately, disturbing the roots as little as possible. The undisturbed portion should rebloom that fall season and can be divided the following summer. Reblooming irises are available locally each spring when nurseries get their stock or through mail order sources that sell them individually or as collections with several cultivars per collection.

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Miriam Jabour, a Master Gardener and Master Flower Show judge, has been active in the Openwood Plantation Garden Club for over 35 years. Write to her at 1114 Windy Lake Drive, Vicksburg, MS 39183.