BEARDED IRIS

I. hybrids (bearded iris, beardless iris, aril iris), I. pseudacorus (yellow flag iris)

There are more than 200 species of irises that grow wild (or did once) and thousands of hybrids, but all have two characteristics in common: sword-shaped leaves and a distinctive flower structure consisting of three usually erect petals, called standards, and three outer petals, or sepals, called falls, that hang down from the base of the blossom. Between each pair of standards and falls rise the flower's reproductive organs, often crowned with colorful crests. Irises come in a stunning range of colors - hence the name iris, after the Greek goddess of the rainbow.

There are two broad categories of hybrid irises - bearded and beardless. On bearded irises each of the falls is ornamented with a fuzzy, often brightly colored strip, or beard. Bearded irises include the familiar standard bearded hybrids as well as the group of hybrids called aril irises, which are distinguished by their rounded flowers, veined petals and subdued colors. The colors of standard bearded irises range from snowy white through every conceivable shade, including yellow, orange, pink, red, blue, lavender, purple, brown, and near black; more often than not the standards and the falls are of different colors. The height of standard bearded irises ranges from 3 inches to 40 inches or more, with flowers 1 1/2 to 8 inches across.

Plant height, flower size and blooming season are the key factors in the American Iris Society classification of standard bearded irises: MINIATURE DWARF BEARDED IRISES, less than 10 inches tall, bear 1 1/2- to 2-inch flowers in midspring. STANDARD DWARF BEARDED IRISES (sometimes called Lilliputs), 10 to 15 inches tall, have 2- to 2 1/2-inch flowers. INTERMEDIATE BEARDED IRISES, 15 to 28 inches tall, have 2- to 4-inch flowers, but both bloom slightly later in spring than miniature dwarf irises. MINIATURE TALL BEARDED IRISES (sometimes called table irises), 18 to 26 inches tall, have flowers up to 2 1/2 inches across; BORDER BEARDED IRISES, up to 28 inches tall, have 3- to 4-inch flowers; and TALL BEARDED IRISES, more than 28 inches tall, have 4- to 8-inch flowers; all three types blossom from late spring to early summer. REBLOOMING BEARDED IRISES, of varying heights and sizes, blossom in spring and again any time from midsummer through fall.

Beardless iris hybrids are classified into four groups: LOUISIANA HYBRIDS grow 2 to 3 feet tall and bear 3- to 4-inch flowers ranging in color from white through cream and yellow to bronze, pink, red, blue, purple and near black; the flowers blossom in mid- to late spring in Zones 8-10 and in early summer farther north. JAPANESE IRISES grow up to 3 1/2 feet tall; their flat-topped blossoms--often 6 to 8 inches across, but sometimes as large as 10 inches--come in many shades and mottlings of rose, purple and blue as well as in white, and bloom in early to midsummer. SIBERIAN IRIS HYBRIDS grow up to 3 feet tall and have 3-inch flowers in many colors from pure white to deep reddish purple with most blossoms in shades of deep blue, purple and violet; they bloom profusely in early summer and are long lasting, some flowers remaining in bloom for a week.

A direct descendent from wild species, the nearly indestructible yellow flag iris bears bright yellow brown-veined flowers, 1 1/2 to 2 inches across, in early to midsummer. It is at its best in wet places, such as beside ponds, and may be planted to grow untended indefinitely, as if wild.

HOW TO GROW:

All irises bloom best in full sun, but soil, moisture and climatic requirements vary with the types. Standard bearded irises do well throughout Zones 3-10 except in Florida and along the Gulf Coast, and will grow in any well drained soil. Bearded irises grow from thick underground stems, called rhizomes, that creep along just beneath the surface of the soil; plant both types from midsummer to early fall, setting them 10 to 15 inches apart, with the tops of the rhizomes even with the surface of the soil. Standard bearded irises multiply rapidly and reach their peak of loveliness in the third and fourth flowering seasons; after flowering, the rhizomes should be dug up, divided and replanted.

Among the beardless irises, Louisiana irises grow best in Zones 7-10, Japanese irises in Zones 5-8 and Siberian irises in Zones 3-8. Louisiana, Japanese and Siberian irises require acid soil with a pH of 5.5 to 6.5; add sulfur if necessary to acidify the soil. Both Louisiana and Japanese irises do best in very moist soil liberally supplemented with peat moss, leaf mold or compost; SIberian irises thrive in moist but well drained soil. Plant all of them in fall 15 to 18 inches apart. All of the other beardless hybrids can be propagated by dividing clumps in early fall. Otherwise they can be left alone for as long as 8 or 10 years, when they may become overcrowded.

Yellow flag irises, which grow in Zones 5-10, thrive on neglect as long as they have moist soil. Space plants 18 to 24 inches apart. Clumps can be left undisturbed indefinitely, or dug up for division to start new plants.