There are approximately 200 species of Iris. Bearded irises are one of the most common perennials in the home garden. Though less popular than the bearded irises, Siberian irises (Iris sibirica) are excellent perennials. They are hardy, easy to grow, and relatively trouble-free.
Iris flowers are composed of 6 segments. The inner 3 upright segments are the true petals and are referred to as standards. The drooping, outer 3 segments are petal-like sepals and are known as falls.
The flowers of Siberian irises are smaller and more delicate than those of the bearded irises. Unlike bearded irises, their falls do not have fuzzy growths or beards. Numerous varieties of Siberian irises are available. They are available in shades of blue, purple, wine-red, pink, white, and yellow. Their flowers are borne atop tall stems in late May or June.
The foliage of Siberian irises is narrow (approximately 1/2 inch wide), upright, grass-like in appearance. The green foliage often turns to an attractive yellow or orange-brown in the fall. Siberian iris varieties range in height from 12 to 40 inches.
Siberian irises perform best in moist, well-drained, fertile soils. However, they will tolerate poor, dry sites. They can be grown in partial shade to full sun.
Siberian irises are usually planted in spring or late summer. However, container grown material can be planted any time during the growing season. Space plants about 18 to 24 inches apart. Plant 3, 5, or more of the same variety in a clump for the best visual display.
To aid establishment, water Siberian irises once a week during hot, dry weather. Water when needed for at least one full growing season.
Plants seldom bloom the first year after planting. Siberian irises should be blooming well by the third or fourth year. They will eventually form large, well-established clumps.
Established Siberian irises don't require a great deal of care. Plants can be lightly fertilized in early spring with an all-purpose garden fertilizer, such as 10-10-10. They can also be fertilized immediately after bloom. A 2- to 3-inch-layer of mulch around the plants helps control weeds and conserves soil moisture. If possible, water once a week during hot, dry weather. Cut back the dead debris in late fall or early spring.
Siberian irises don't have serious insect or disease problems. Unlike bearded irises, they are seldom bothered by the iris borer, soft rot, or leaf spot.
Division is rarely necessary for Siberian irises. Divide Siberian irises when clumps become crowded or when flowering decreases. Clumps can be divided in early spring at the first sign of growth or immediately after bloom.
Home gardeners can choose from numerous Siberian iris varieties. Suggested varieties include:
- Butter and Sugar-white standards, yellow falls, 28 inches tall.
- Caesar's Brother-dark purple flowers, 36 inches.
- Dreaming Yellow-cream standards, pale yellow falls, 30 inches.
- Eric the Red-dark wine-red flowers, 36 inches.
- Flight of Butterflies-violet-blue standards, white falls with butterfly-wing pattern of violet-blue veins, 36 inches.
- Halcyon Seas-medium violet-blue flowers, 36 inches.
- Jeweled Crown-deep wine-red flowers, falls have large circular gold blaze which fades to white, 24 inches.
- King of Kings-large white flowers, 36 inches.
- Lady Vanessa-light wine-red standards, ruffled medium wine-red falls, 36 inches.
- Little White-white flowers, 12 to 18 inches.
- Orville Fay-medium blue with darker blue veins, 36 inches.
- Pink Haze-pink-lavender flowers, 38 inches.
- Ruffled Velvet-violet standards, darker falls, 24 inches.
- Savoir Faire-deep blue flowers, 36 inches.
- Snow Queen-white flowers, 32 inches.
- Sparkling Rose-rose-pink flowers, 30 inches.
- Spring's Brook-blue-violet flowers, 40 inches.
- Sultan's Ruby-deep magenta flowers, 30 inches.
- Super Ego-light blue standards, lighter falls, 30 inches.
- Wing on Wing-White ruffled flowers, 36 inches.
When selecting perennials for the home garden, be sure to include Siberian irises.
This article originally appeared in the March 28, 1997 issue, pp. 29-30.