The Rainbow Flower

During cold winter months when temperatures raise high enough to start snow and ice melting, many gardeners turn their thoughts to spring and visions of gardening once again. Whether planning a new flower garden or revising an established one, the iris is a plant worthy of consideration for a place in any garden.

 

The iris is a member of the iridaceae family which is quite extensive and varied. Iris have been cultivated for centuries not only for their herbal and medicinal properties but as heraldic symbols as well. They were a favorite of royal gardens as early as the 19 th century. The iris derives its name from Greek mythology. “Iris” was named “goddess of the rainbow.” As a messenger for the Greek Gods she was represented as the beautiful maiden who wore lovely robes of many colors. Iris delivered heavenly messages to earth by riding the rainbow (space between heaven and earth) with her robe of many colors trailing as she rode across the sky.

 

Although there are many different varieties now available, almost all irises have at least two characteristics in common-their sword shaped leaves and a distinctive flower structure. All iris bear flowers which consist of 6 six petals-three inner upright or arched petals known as “standards” and three outer petals called “falls” which hang down from the base of the blossom at various angles. It is the unique feature of the falls which determine the category to which the iris belongs. Those irises which have fuzzy hair (similar to “five o’clock shadow on the face) on each of its falls are said to be “bearded.” If the falls contain a yellow comb like ridge, those irises are said to be “crested.” Any iris which has neither is referred to a being “beardless” (their falls are smooth).

 

The bearded varieties are also known as pogon or Iris Germanica; they dominate the market. All bearded irises grow from fleshy roots known as rhizomes and most flower for two to three weeks during late spring. April and May are considered to be their most prolific months. Some of the newer cultivars, however, will rebloom from summer into fall. The second display of blossoms is generally not as showy as the original ones produced in the spring. There are enough different hybrid varieties available to have different irises in bloom from early spring through fall. With the exception of clear red, this class of irises can produce blossoms ranging from white to almost any color or combination of colors. The standards and falls of the iris may be of the same or contrasting colors.

 

There are iris varieties which can range from as tall as 40 inches to as short as 3 inches making it possible for iris to showcase various areas of your flower garden. The dwarf varieties also look great in rock gardens.

 

While the tall bearded iris is relatively easy to grow, they must be planted in full sun in soil with good drainage. The iris can tolerate light shade but shade which is excessive may reduce or even prevent flowering altogether. Soggy soil can cause the rhizomes to rot. When planting rhizomes, dig a hole 8-10 inches deep and about twice the width of the rhizome. Make a small mound in the hole and plant the rhizome making certain the top half is above the surface of the soil so it is exposed to the sun. Individual rhizomes can be planted 6-8 inches apart in an open bed. To achieve an attractive array of irises, try setting 3 rhizomes together in a triangle, making certain they are at least 2 inches apart in the center. Keep in mind, the bearded iris will grow in the direction that the leaf end of the rhizome is pointing. Planting the iris facing each other will produce crowding as the iris will eventually grow into each other.

 

After 3-4 years the rhizomes will probably start to become crowded and then it will be time to divide them. Years of growth may have produced extensive root development but the centers will lack the necessary energy to continue producing these lovely blossoms which you have grown to like so well in your garden. Division can produce either single or double fans. The best division are those with two smaller rhizomes growing at angle to the larger one thereby forming a “y.” The double or “y” fans will produce the best show of flower in the first year. The ones with single fans will perform equally well but it will take longer to achieve this effect. The best time to divide bearded irises is after they have finished blooming and are resting. They are less likely to be “stressed” by being dug up and cut.

 

A second class of iris is the beardless or apogon which differ from the bearded in that there is less variety of height and color. Unlike the bearded iris, many of these plants will perform best when planted in moist, shady areas of the garden and require only a half day of filtered light.

 

Of the more common beardless varieties available, the Siberian irises are the easiest to grow as they are the most forgiving. These plants do, however, take a season or two to become established and resent being moved. Divide them only when they become so crowded that blooming is reduced. This iris is an excellent choice for moist sites in the garden which are often not receptive to other plants. They will even grow with up to two inches of standing water over their crowns. They produce clumps of narrow grass like leaves and three inch wide flowers which bloom profusely in early summer. Their two-five blossoms come in white and shades of blue and purple. Thanks to the many cultivars now available, this iris can even be found with bicolor blossoms. The Siberian iris would be an excellent choice for a sunny perennial border.

 

Another of the beardless varieties is the more specialized plant known as the Japanese iris. These plants have graceful upright leaves but their blossoms which can be either single or double, are essentially flat. The single blossoms have three broad falls and a reduced number of standards giving the flower a triangular outline. The plants with double blossoms have standards and falls about the same size and shape which results in a more circular flower. The Japanese iris bear their flat-appearing four-eight inch blossoms during the early to middle summer months in shades of violet or lavender blue, purple, white, rose pink or wine red. They require full sun to partial shade and soil which is quite acidic (pH 5.5-6.5) with constant moisture-even soggy in the spring and summer. These irises perform best when planted in moist borders, at the edges of pools or streams or in containers partially submerged in a pond or pool during the growing season.

 

The Louisiana irises (sometimes referred to as swamp irises) are hybrids derived from several native species and range in height from 1 ½ or 2 feet to 5 feet and spread to 3 feet or more via the wide spreading rhizomes. They require full sun to partial shade and bear flowers in shades of purple to blue-black, sky blue, vermilion red or violet from midspring to early summer. This iris also requires very rich, constantly moist to wet acidic soil.

 

The spuria iris grow to a height of more than three feet and produce a four inch flower in the spring and early summer. These flowers are available in white, cream, yellow, brown, purple, blue and are excellent for cutting. As these plants usually require 2-3 years to become fully established, they should remain undisturbed indefinitely. Many of the beardless irises can be left 8-10 years before they become overcrowded and require division. These plants form a very tough network of smaller, flesh roots which can be difficult to divide and their division may even require the use of an extra instrument.

 

Although there are less varieties of beardless iris to choose from, they could be the “perfect” solution for that problem area in your garden.

 

The third class identified as “crested” or Evansia are often considered in the same manner as the beardless iris. These plants spread freely by underground stems and produce flat flowers in the shades of blue, violet and white. Often the flowers and leaves are found on bamboo like stems which can vary in height from 5-200 centimeters in height. Wooded areas with good drainage and partial shade are ideal spots for the crested iris.

 

The iris family, so varied and colorful, is able to offer the gardener many opportunities in which to showcase his/her garden. When making a selection, the gardener should always take care to heed any instructions which may be specific to the variety purchased or being considered for purchase.

 

Call the UNH Cooperative Extension's Family, Home & Garden Education Center 's Info-Line toll-free at 1-877-3984769 for "Practical Solutions to Everyday Questions." Trained volunteers are available to answer your questions Monday through Friday from 9 am to 2 pm .

 

By Marilyn Kelley, Master Gardener, UNH Cooperative Extension, Hillsborough County