Native irises carry Louisiana name worldwide

Richard Bogren, Huffstickler, Kyle, Gill, Daniel J., Owings, Allen D.  |  3/18/2011 1:05:22 AM

Louisiana iris is the name for a unique group of native iris species and their hybrids.

News Release Distributed 03/18/11

By LSU AgCenter Horticulturists
Dan Gill, Kyle Huffstickler and Allen Owings

Blooming from late March to early May, the Louisiana iris is a floral ambassador that has carried our state’s name all over the world.

Louisiana iris is the name used worldwide for a unique group of native iris species and their hybrids. Their extraordinary beauty and reliability in the garden have made them increasingly popular, but they still deserve more recognition and use here in their home territory. The Louisiana iris is our state’s official wildflower.

Though a number of iris species are native to Louisiana, only five species – Iris brevicaulis, Iris fulva, Iris giganticaerulea, Iris hexagona and Iris nelsonii – are known as “The Louisianans.”

Only in south Louisiana do all five species occur together. They are closely related and will interbreed with each other but with no other species. The crossing, or interbreeding, of these species has resulted in the modern hybrid varieties we grow today. Their large, attractive flowers cover a broad range of colors, including many shades of blue, purple, red, yellow, pink, gold, brown, lavender, burgundy and white.

Be sure to not confuse Louisiana irises with the yellow and blue flag irises. Louisiana irises are much better performers.

The best time to plant Louisiana irises is in August and September when they are dormant, but you can buy and plant them as well while they are in bloom in spring with good success. When purchased and planted in spring, however, Louisiana irises need to be handled carefully to avoid damaging the foliage and flower buds. And you may need to stake the plants to hold them upright after planting. But once they’re established, Louisiana irises don’t need staking.

Louisiana irises should be grown with as much direct sun as possible. Although they will tolerate shade for part of the day, at least six hours of direct sun are needed for good blooming. You can plant Louisiana irises in beds by themselves, combined with other perennials or even in aquatic gardens.

When preparing a spot to plant them in a typical bed, incorporate a generous 3-inch layer of compost, rotted manure or peat moss and some all-purpose fertilizer into the soil. These irises grow best in a soil high in fertility and organic matter.

Aquatic culture is one of the easiest and most natural ways to grow Louisiana irises – and the foliage tends to stay more attractive during the summer. Simply place a potted iris into your decorative pond or aquatic garden so the rim of the pot is a few inches below the water’s surface. These plants also grow well and look great planted in the ground on the edges of large ponds. They also are excellent plants for rain gardens.

The large seedpods that form after flowering should be removed as soon as you notice them to keep the plants more attractive and vigorous. Next fall, in October or November, fertilize the irises as they begin their winter growing season.

Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.lsuagcenter.com/lahouse and www.lsuagcenter.com/lyn.

Rick Bogren

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