The Best Flower for Spring the Iridescent Iris

Irises are exotic looking perennial flowers that offer a huge range of colors and patterns, heights, and bloom times, with variations on a common theme of flower shape and plant form. They have a lovely sweet spring scent. By far the most popular group is the large collection of hybrids termed the “bearded” irises, named for the hairy caterpillar-like tuft creeping out of the center of each fall. They bloom in late spring and early summer, from 2 inches to nearly 5 feet above stiff, sword like leaves. A number of cultivars rebloom from late summer into fall, to double the show; these reblooming cultivars are worth seeking out. The USDA Zones chart says they grow in zones 3–8, but I live in Las Vegas zone 9b and they grow proficiently in our dry hot climate.



How to grow Most bearded irises are easy to grow, but they do have specialized needs. Plant and divide every 3 to 4 years in summer or early fall, splitting them into individual “fans” with the rhizome attached, or into divisions with a few fans. Trim leaves back before planting to make up for root loss. They grow best in full sun or very light shade and average to rich, well-drained soil. Barely cover the rhizome and point the leafy end in the direction you want it to grow, ideally out from the center of a group of three to five of a kind. Bearded irises tolerate drought very well when dormant (usually beginning about six weeks after bloom), but water them well up to the time dormancy sets in and after division. Fertilize routinely in spring and early fall, keep weeds and other plants away from the rhizomes, mulch loosely the first winter after division, and be ready to stake the tall cultivars when they bloom. Soft rot attacks during wet seasons in poorly drained soil, entering though wounds in the rhizome made from premature leaf removal or too-close cultivation; it can also be carried on the body of the iris borer. The eggs of this pest hatch in spring, producing 1- to 1½-inch-long, fat, pinkish larvae. The larvae enter a fan at the top and tunnel down toward the rhizome, where they may eventually eat the whole interior without being noticed. In fall, remove dead, dry leaves, which often carry borer eggs, and destroy badly infested fans in spring. You can also crush borers in the leaves by pinching toward the base of the telltale ragged-edged leaves or by running your thumb between the leaves and squashing any borers you find. They are also vulnerable when you divide the clumps; check every rhizome for this pest. If you find a few borers, try cutting them out, but destroy badly infested rhizomes. Landscape uses: Smaller bearded irises are perfect in rock gardens and along paths and beds. For mid- to late-spring bloom, plant taller ones in a perennial border, or in a separate bed to provide optimum conditions. They also look splendid among garden ornaments and along patios.