Tooele Transcript Bulletin – News in Tooele, Utah

May 30, 2013
Growing irises in Tooele County easy due to alkaline soil

Do you have a hankering to visit a tropical island so you can see beautiful, exotic flowers? Perhaps the only thing standing between you and going after that dream is dollars.

Take heart. You may not be traveling to the tropics this season, but we have some exotic looking flowers that will grow well here.

Irises look exotic and are reminiscent of orchids. They are pretenders that rise tall and regal above sword-shaped leaves. Often, several blossoms appear on a single stem. They come in such an array of stunning colors and mixtures, that they are named after the Greek goddess of the rainbow, Iris.

The bearded iris commonly grown in our area may range from 3 to 40 inches in height with flowers 1 1/2 to 8 inches across.

Despite the blossoms’ fragile appearance, irises are sturdy plants that just love life in Tooele County’s climate and alkaline soils.

Bearded irises are very hardy and have been a common flower here since the first pioneer settlers arrived. They are one of the few flowers that can survive without supplemental irrigation. In fact, unlike so many lovely flowers that local people covet, nurture and tend all summer, irises want exactly what we have to offer naturally.

Garden books describe their cultivation as “requiring a well drained, preferably alkaline soil with open, sunny locations without too much water.” They are often found growing in pioneer cemeteries where they have received little or no attention for many years and they thrive equally well in harsh urban landscapes.

There seems to be no end of iris types, sizes and shapes. More than 200 species grow wild throughout the world with thousands of others hybridized by plant breeders.

The familiar bearded irises appearing now in our area grow from rhizomes. Irises are also classified into another group, bulbous, which means they grow from bulbs.

Bulbous irises are the Dutch iris, as well as English, Spanish and juno species. They are planted as spring-flowering bulbs. Some varieties appeared early this spring and finished blossoming some time ago.

Nearly all irises produce sword-shaped leaves. Their blossoms include three, usually erect, central petals known as “standards,” and three outer petals called “falls” that hang below. The reproductive structures are located between the standards and falls.

Hybrid irises are further divided into bearded and beardless. Bearded irises have a bright colored strip or beard running down the center of each of the falls.

For the most part, irises grow pest-free. While some borers attack the rhizomes, they are uncommon and best controlled by discarding affected plants. Treat for slugs and snails with dry bait. Disease problems are minimal provided the plants are not overwatered. Decaying rhizomes, the only common disease in our area, normally only occurs in wet, poorly drained soils. Improve drainage in clay soils by planting the flowers in raised areas.

Some growers are discouraged when the plants do not bloom freely. Several cultural practices encourage better blooming.

Bearded irises are propagated by thick, underground stems called rhizomes which grow beneath the soil 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.

Dig crowded clumps soon after they bloom. Replant them during the summer months so they have time to establish a good root system and store enough energy before winter to bloom the following spring.

Irises are vegetatively propagated and are sold as rhizomes with clipped roots and leaves. A plant can remain out of the ground for a week or two without serious harm, but the sooner it is planted, the better.

Plant them in a sunny spot in well drained soil. Turn the soil to a depth of at least 10 inches. Spread fertilizer and work it into the top of the soil two to three weeks before time to plant. A well prepared bed will result in better growth and more bloom.

Don’t starve your irises or make them compete with nearby grass or weeds for food and water. Consider getting a soil analysis, and then add the fertilizer of the kind and quantity the tests show the soil needs.

The soil should be light. If it is clay soil, add compost. Manure should be used only after it has aged for about a year. Otherwise, it may cause rot. Bury rhizomes near the soil surface and pack roots into the soil firmly enough to hold the plant in place. You might wish to dig two trenches with a ridge between them, place the rhizome on the ridge and spread the roots carefully in the trenches. Be sure to firm the soil tightly and allow enough for settling to keep the rhizome above any possible standing water. Then fill the trenches with soil, leaving the top surface of the rhizome barely beneath the surface of the soil.

If you have several plants, place them at least a foot and a half apart, facing the same way. The rhizomes will then increase in the same direction, and won’t crowd as soon.

In about two or three years, the new rhizomes will begin to crowd each other and you will want to divide the plant, cutting the newer parts of the rhizome free from the old, which may then be discarded. Unlike the other bearded irises, arils need to be transplanted annually.

You will have so many new rhizomes that you will share them with your friends. Perhaps you received your first rhizomes from a friend. These rhizomes don’t mind too much if they have to lay out for a few days before they are replanted.

When digging, keep all plants carefully labeled with their names, for sure identification. It is wise to keep diagrams of your planting area to double check individual labels on the plants.

Fertilize infrequently and then only lightly with a high-phosphate fertilizer. Adding too much nitrogen forces green growth and discourages flower formation. They don’t need fertilizer every year. Some iris enthusiasts use a light sprinkling of super phosphate fertilizer very early in the spring before the leaves begin to fan out. Fertilizer should be applied around the plants so the roots grow into it rather than on the tubers where it might cause burning.

You can still have surprises from irises even though they live well here. Some varieties will flourish better in your garden than others. Some colors may even change under different soil and garden conditions.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>