To imagine a flower better adapted to our local conditions than the iris would be difficult. Cultivation requirements for iris are described as "requiring a well drained, preferably alkaline soil with open, sunny locations without too much water." That description fits most of the state of Utah and many surrounding areas.
More than 200 species of iris grow wild throughout the world, and thousands of different hybrids have been created by plant breeders. Iris are divided into two groups, bulbous, which grow from bulbs, and rhizomatous, which grow from rhizomes. Bulbous iris comprise the reticulatas and the juno species as well as the English, Spanish and Dutch iris. Bulbous iris are generally used as spring blooming bulbs or planted among herbaceous perennials.Rhizomtous iris are the familiar "flags" that are so showy in our area. Almost all iris share two common characteristics. They have sword-shaped leaves and a distinctive flower structure with 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 are the flowers' reproductive structures. These are often crowned with colorful crests that give them their antiquated name of flags.
Hybrid iris are further divided into bearded and beardless. Bearded iris have a bright-colored strip or beard running down the center of each of the falls. Iris come in such a stunning range of colors that they are named after Iris, the Greek goddess of the rainbow. Colors range from snowy white to almost every conceivable segment of the spectrum, including yellow, orange, pink lavender, blue, red, brown, purple and almost black. Standard bearded iris range in height from 3 to 40 inches, and their flowers are a half-inch to 8 inches across.
The American Iris Society classifies standard bearded iris into miniatures that are less than 10 inches tall with one-half- to 2-inch flowers and standards ranging from 10 to 15 inches with 2- to 21/2-inch flowers. Intermediates are 15- to 28-inches tall with flowers of up to 21/2 inches. Border bearded are up to 29 inches tall with 3- to 4-inch flowers, and tall bearded are more than 28 inches tall and have 4- to 8-inch flowers. They also have a special category for reblooming bearded iris, which blossom in the spring and again later in the season.
Bearded iris are very handy and will grow in all climates in Utah. I don't know when the earliest cultivated iris arrived in the state, but it has been a common flower here for more than a hundred years. They are one of the few flowers that can survive without supplemental irrigation, and you can often find them growing in pioneer cemeteries where they have received little or no attention for many years.
Bearded iris propagate by thick, underground stems called rhizomes. These grow beneath the surface and produce new plants. Although the plants do not require much attention, they grow and bloom better if the rhizomes are dug, divided and replanted every three or four years.
Another indication of how tough and well adapted iris plants are is that plants that require dividing need to be dug soon after flowering and replanted during the summer. That allows them to establish a good root system before winter so they can store enough energy to bloom the following spring.
Iris suffer few pest problems. Borers that attack the rhizomes are not common and are best controlled by discarding affected plants. Diseases are not likely to be a problem if the plants are not overwatered. Decaying rhizomes constitute the only frequent disease, and normally occurs only in wet, poorly drained soils.
The most frequent complaint of lack of blooms is due to several cultural problems. Iris do not bloom if the planting is too crowded. Dig the rhizomes after they bloom, then separate and replant them. They do not bloom freely if planted in shady areas. Move them to a sunny location to solve that problem. One final problem is that iris do not bloom if they are competing with other plants. Remove the weeds to encourage large, abundant blooms.
- THE UTAH IRIS SOCIETY will hold its 48th Annual Iris Show at the Garden Center in Sugarhouse Park near Highland High School. The show is open to the public Saturday, May 14, from 1:30 to 6 p.m. and Sunday, May 15, from 10 a.m. to 5 p.m. Anyone can enter iris specimens, but the iris must be identified by name. Entries will be accepted between 8 a.m. and 10 a.m. on May 14.
- THE BEEHIVE STATE CHRYSANTHEMUM SOCIETY will hold a plant sale at the Garden Club Center on Saturday, May 14, from 9 a.m. to 2 p.m. You may purchase mum plants while viewing the Iris Show.
- CODLING MOTH SPRAYS to prevent wormy apples and pears should start this weekend. Recommended sprays include Imidan, Diazinon or Bt. Check next week's article for complete details on future spray intervals.