1288 Iris sibiricaCommon Names: Siberian iris,Siberian Iris group Family: Iridaceae (iris Family)
Iris flowers are distinctive. They have three large floppy petals that can be spreading, hanging or bent backwards. These are called falls. They also have three smaller petals that are erect or spreading, called standards.
The rhizomes of Siberian irises run just below the ground surface and each season give rise to one or more new basal tufts of narrow, grasslike leaves. In this way Siberian irises eventually form large clumps. Siberian iris leaves are around 18 in (45 cm) long and arranged like a fan. Some irises are evergreen, sporting above ground foliage all year long, but not the Siberian irises; their leaves turn brown in autumn and wither to nothing in winter, to reemerge in spring.
In late spring or early summer, Siberian irises flaunt one to five (usually three) flowers, each 2-3 in (5-8 cm) across, well above the leaves on erect, branched stems that are hollow. The species, Iris sibirica, has violet-blue petals, with the falls having darker veining and white bases. The other species and cultivars in the Siberian Iris group have flower petals that can be red, yellow, pink, white, blue, purple or even black. Some have white or yellow splotches on the bases of the falls. Some are streaked with darker hues. Some have ruffled petals. Some are larger and more robust plants, to 3 ft (1 m) or more in height. Some are fragrant.
The nine species in the Siberian iris group occur naturally in moist meadows and open woods in mountainous areas within central and eastern Europe and much of Asia. The parents of the majority of cultivars are Iris sibirica, which occurs from Central Europe to Russia, and I. sanguinea, which is native to Siberia, China, Korea and Japan. Siberian iris has escaped cultivation and become established in Ontario, parts of the northeastern US and in Washington and British Columbia.
Light: Siberian irises do best in full sun up North, but need protection from the mid-day sun in hotter climates. Moisture: Siberian irises are more tolerant of drying out than most other iris types, but they still like a soil that stays moist, as long as it is not soggy. They need an inch (25 mm) or more of water per week to be at their best. Don’t let them dry out during the spring and early summer growth period. Siberian irises thrive in a soil rich in organic material, with a slightly acidic pH of 6.0 - 7.0. Hardiness: USDA Zones 4 - 9. Protect from mid-day sun in zones 8 and 9. Propagation: : Separate plantlets by cutting their rhizomes. Try to get two or three plantlet clumps in each division and plant the rhizomes about an inch (2.5 cm) deep. This is best done in spring.
The Siberian irises are among the easiest perennials to grow. They persist without our help for years, even in grassy lawns and weed-filled old home sites. Siberian irises are adaptable to most soil types and are an excellent choice for low maintenance gardens. They combine well with other herbaceous perennials in mixed borders and are effective when allowed to mass on a slope or along a stream or pond. The foliage is attractive even when the irises are not in bloom.
Siberian irises are excellent as cut flowers, but they last only a couple days.
The Iris genus is taxonomically confusing and has no doubt led to premature balding for some botanists. There are some 300 species of irises and thousands of named cultivars. Recent authorities have grouped iris species into several sections, and then combined some of those sections into subgenera within the genus Iris. The Siberian irises are in the Section Sibiricae, within the Subgenus Limniris, and by most counts, include nine species: Iris sibirica, I. bulleyana, I. chrysographes, I. clarkei, I. delavayi, I. dykesii, I. sanguinea, I. wilsonii and I. forrestii.
Horticulturalists take a similar, albeit slightly simpler, approach, dividing all the irises into several groups (see What’s in a plant name), within a handful of unique categories. Bulbous irises arise from a storage organ called a bulb. Rhizotomous irises lack a bulb and instead spread on shallow root-like rhizomes. Bearded irises have a patch of “hairs” in the center of each fall petal. Beardless irises have smooth falls lacking the hairs. The Siberian Irises are one of six groups of irises that are beardless and rhizotomous. The Siberian Iris group includes the nine species listed above and 150 or so named cultivars registered with the American Iris Society. The majority of the Siberian iris cultivars come from crosses between I. sibirica and I. sanguinea.
See the Floridata article, All About Irises for lots more information about these popular garden perennials.
Steve Christman 5/11/17