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Complex hybridization has resulted in an astounding variety of irises to choose from. With careful planning, Colorado gardeners can extend the bloom time of iris over many months in their gardens.
Their unique shape characterizes Iris flowers. The three outer sepals of each flower are called "falls," and have a fuzzy central portion called a "beard." The inner petals are upright and called "standards." The edges of the petals are sometimes ruffled. Their lovely flowers are available in every color and color-combination imaginable. Little wonder that early botanists named this beautiful flower in honor of Iris, goddess of the rainbow.
One of the earliest bloomers, in late February to
early March, is the bulbous reticulata iris, Iris danfordiae . This tiny iris, four to six inches in height, bears a single yellow flower. Its falls are sprinkled with greenish-brown "freckles." Blooming so early, it calls out to the winter-weary gardener, "spring is coming!"
A few weeks later, in mid to late March, several other species of reticulata iris make their appearance. Most of these are in the color range of purple, indigo or sky blue. Varieties commonly available in Colorado nurseries are I.'George,' which bears sturdy rich purple flowers, I.'Harmony,' which produces royal
blue flowers with a central yellow mark on each fall, and I.'Histrioides,' which bears dark blue flowers. The falls of I. 'Histrioides' have deeper blue spots on them and have a yellow center ridge.
Plant Iris reticulata bulbs along with crocus bulbs for a heavenly early spring spot in your garden. Iris reticulata bulbs are available in the fall in neighborhood garden centers. They should be planted two to four inches apart at a depth of at least twice the size of the small bulb.
In mid-season, just as deciduous trees begin to leaf out, dwarf irises (eight to twelve inches tall) begin to bloom. These beauties, planted in front of a perennial border or in a rock garden, offer a wide spectrum of color. Varieties usually available in Colorado nurseries include I. 'Chubby Cheeks,' which bears ruffled, light violet-edged white flowers with tangerine tipped violet beards. Also, I. 'Cotton Blossom,' that offers ruffled creamy white flowers, I. 'Dark Vader' with ruffled, dark blue-violet standards and black falls with violet beards, and I. 'Eyebright' that produces bright yellow flowers. Its falls have deep down brown lines and deep yellow beards.
Throughout May and June the more familiar bearded irises, sometimes called "German irises," break into bloom. These glorious flowers, growing up to three or four feet in height, come in a rainbow of colors too numerous to describe. Intermediate, border, and several tall bearded types sequence through the blooming season. These are followed by beardless Siberian, Spuria and Japanese iris that bloom through mid-summer. All together, the many types of iris offer at least five months of bloom.
There are several iris farms in Colorado and it may be best for gardeners to visit one when the bearded irises are in full bloom. That way, gardeners can plant irises that correspond to the color scheme of their garden. Given the glorious array of colors, the temptation in visiting an iris farm is buying more plants than are actually needed.
Irises bloom best when they are planted in full sun. They are drought tolerant and do well in xeriscape gardens.
- Each rhizome (the fleshy root-like stem) should be set in a shallow
hole so that the top of rhizome is one inch or less beneath the soil.
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In perennial borders that need consistent watering, the top half of
the iris rhizome should be left exposed so that it will not rot from
being over watered.
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Don't plant other perennials so close that they crowd the rhizomes
and hold in moisture.
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Don't mulch, it will also lead to rot.
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The roots attached to the rhizome need to be covered with soil.
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Position the rhizome so that the fan of leaves faces the direction
in which you want the plant to grow.
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Allow 12 to 15 inches between each plant.
With the exception of reticulata iris, which have
rounded, dark green leaves similar in shape to chives, and Iris
pallida 'Variegata,' which has green and yellow striped leaves, all other irises have gray-green sword-like leaves. Iris leaves form a wonderful, vertical accent to provide textural contrast to other
rounded foliage in the garden. Because the plants are semi-evergreen, contributions from the foliage continue through most of the year, including the winter months.
One thing is certain about irises. The gardener who plants them will have found a proverbial pot of gold at the end of the rainbow.
For more information on Gardening, contact your
local Colorado State University Extension office. |
