Plants that combine elegant beauty with extreme toughness are a hard combination to beat. Perhaps none are more successful than the iris. The exquisite blooms are so showy that they are often called poor man's orchids. Yet these same plants are so hardy that they will survive in our harsh desert climate with almost no irrigation.
Imagining the month of May without these stately flowers is difficult. I first knew them as "flags." I suspect we called them that because of how we used them. The tall upright flower stalks were mostly deep blue and their bloom came in time for Decoration Day, or Memorial Day as we now know it. Early that holiday morning we would visit the iris beds and find those that were in full bloom. We would transport these to the cemetery and carefully arrange them on the graves of departed loved ones. This tradition carries on even today. The iris blended with the hundreds of American flags placed to honor the Armed Forces veterans. This and their tall, stately appearance gave the flowers the common name of flags.Although these flowers have a long association with this holiday, they are interesting and attractive for many reasons. They provide intense garden interest throughout the spring and even beyond if you select the right varieties. The many species and the hundreds of varieties make these flowers an excellent choice for many situations. Never limit yourself to the traditional blue ones because there are so many more that add so much.
To understand why these plants are so tough, look at the underground portions. Bulbous irises bloom earlier in the spring and propagate differently than those with rhizomes. These thick fleshy underground rhizomes contain buds that propagate the plants. These fleshy stems allow the plants to survive long periods without water. Additionally, the thick straplike leaves are covered with waxy cuticle that further inhibits water loss from the plant. Another adaptation allows them to share their beauty at this time. They bloom in the spring, so their time of highest water use is when water is usually available from natural sources. The rest of the year the plants are in a maintenance mode and use very little water. Yet these same plants happily blend with many other flowers if they are not overwatered.
Plant irises in sunny spots in well-drained soil. Prepare the soil with a garden fork to a depth of 10 inches or more. Spread fertilizer and compost and work it into the top of the soil before planting. Don't starve the plants or make them compete with grass or weeds. Bury the roots firmly to hold the plants in place, but leave the rhizome near the surface.
Space plants at least 1 1/2 feet apart, with the rhizomes "facing" the same way. The rhizomes will increase in the same direction, without crowding each other too soon. From the new parts of the rhizome, new bloom stalks will emerge and create new flowers by vegetative propagation. After two or three years, the rhizomes begin to crowd each other. Divide the plants by cutting the newer parts of the rhizome free from the old. Digging and separating is best done soon after the bloom season. This allows the plants to root and build enough nutrients to bloom the following season.
Garden irises fall into two main groups: bearded iris and beardless irises. Tall Bearded are the most widely grown, but others are just as easy to grow. Each group has unique qualities.
Beardless irises are grown differently than bearded irises. They are transplanted in the fall or in early spring. Never allow their roots to dry out while they are out of the ground and water heavily after transplanting. Siberian irises and some natives can tolerate light shade, but the Spurias Japanese and Louisiana demand full sun. Louisianas and Japanese require moist conditions. All, except Louisianas, should be planted in a permanent spot where they can remain for many years as they resent being disturbed. All are heavy feeders and need to be fertilized regularly.
Thick, bushy "beards" on each fall (lower petals) of the blossoms identify bearded irises. The American Iris Society divides these into six groups for judging awards.
Miniature Dwarf Bearded are the smallest with stems from 2 inches to 8 inches tall. They are the earliest to bloom. They are most effective in rock gardens or planted mass for a "carpet of color."
Standard Dwarf Bearded range in height from 8 inches to 15 inches. They begin blooming early in the season and are best displayed in groups.
Intermediate Bearded are 6 inches to 28 inches high, with a midseason bloom. Some show best in clumps while others are showiest in specimen plantings.
Border Bearded are small versions of the tall bearded with the same height range and bloom size as the intermediates but blooming with the tall beardeds. They have round, ruffled petals that complement their small size.
Miniature Tall Bearded are 16 inches high and are distinguished by daintiness and delicacy. The blooms are smaller than other tall bearded and the stems are thick and wiry. A clump looks like a cloud of butterflies. They are often called "Table Irises" because they are so well suited for arrangements.
Tall Bearded have stalks over 28 inches tall, that branch and have many buds. Each stalk makes a stately display in the garden or in a vase. Besides the wide variety of colors and patterns, they display other qualities (such as ruffling and lacing) more frequently than the other classes.
Even if you grow nothing but bearded irises, there is a remarkable range of colors and a bloom season that extends for months. Some bearded irises are "rebloomers," blooming again in the summer, fall or winter. Additional water and fertilizer during the summer encourages them to bloom again.
The Utah Iris Society will present its 51st Annual Show on Saturday, May 24, from 1 to 8 p.m. and Sunday, May 25, from 9 a.m. to 5 p.m. The show will be at Red Butte Gardens visitor center. For directions to the gardens, call 581-IRIS. They invite the public to enter specimens, but all entries must be correctly named and labeled to be accurate.