February 2018

Some irises bloom twice a year

'Sugar Blues' iris blooms in spring and again in late summer. © Jo Ellen Meyers Sharp

Two favorites in the perennial garden are German or bearded iris and Siberian iris.

Siberian irises (Iris sibirica) are the easiest. They bloom about the same time as columbine (Aquilegia) and perennial salvias in late spring and early summer.

One of the oldest and most popular is ‘Caesar’s Brother,’ a deep blue, delicate beauty, but there are several others.

Siberian iris, a clump grower, is not terribly picky about soil. It prefers a moist, acidic site, such as a bog or edge of a pond, but it seems just as happy in an average perennial garden, including Indiana’s alkaline, clay soil. Once established, Siberian iris is quite drought tolerant. It can be grown in full sun to part shade.

Blade like foliage retains a healthy green hue until fall, when it turns lovely shades of red. Cut the leaves back to the ground in winter. If the center of the plant dies, lift, divide and transplant in spring, tossing the dead parts.

'Caesar's Brother' Siberian iris. Photo courtesy

The big break through of bearded irises (Iris) is the rebloomers — they bloom in spring or early summer and then again in late summer or early fall. I have two, ‘Sugar Blues’, which blooms a bit earlier than ‘Immortality’, with white flowers.

German or bearded irises are a bit pickier. The plants do best in full sun. The rhizomes should be visibly growing along the soil surface. The plant will not bloom and will likely rot when rhizomes are planted too deep or in wet soil. These irises also may fall victim to iris borer, an insect Siberian irises seem less bothered by. To help control the bug, cut back and discard foliage in late summer or early fall.

Iris show at Holliday Park

For more information about irises, check out the Indiana Iris and Daylily Society’s annual iris show, 1 to 4 p.m., May 19 at the Nature Center at Holliday Park.

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