The Homeowners Column

The Homeowners Column

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Dividing iris

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

Goddess of the rainbow. Eye of heaven. Fleur-de-lis. Pretty lofty names for a flower, but iris can hold up to the hype as one of the oldest perennial flower. A patch of flowering iris for me prompts memories of family trips and my great Aunt Evelyn's iris garden. After a long meandering car trip through the hills and hollers of Indiana the iris was the first to greet us with a riot of rainbows and the smells of grape juice and fruit punch.

Many of the over 300 different species of iris are exciting additions to the flower garden. However, the one often inherited from family members is the bearded or rhizomatous iris with its myriad of flower colors, sizes, flowering times and fragrances.

Each thick underground stem called a rhizome produces a bloom stalk only once with the newly developing rhizomes flowering the next year or with the reblooming iris in late summer. Yes, reblooming iris are available that rebloom in September. Rebloomers can be divided in the same way as the one-time bloomers, although I've discovered they require dividing more often than the one-time bloomers.

The best time to plant or transplant iris is after flowering through August. Iris are one of the few perennials to transplant during the hottest part of the year. Established plantings of iris should be divided every 3-4 years or whenever the clump becomes crowded and flowering decreases.

The good news is iris are easy to dig with plenty of divisions to share with family and friends. To divide iris, carefully lift the iris clumps with a spade or spading fork. Shake most of the soil off the roots. Take a sharp knife and cut the rhizomes apart discarding the center old rhizome with the old flower stalk. Be sure the new rhizome has some roots, 3-4 inches of rhizome and a fan of leaves. Cut the fan of leaves back to 6-8 inches tall.

New rhizomes should feel firm. Soft rhizomes may indicate root rot or iris borers and should be discarded into the compost pile. If iris borer caterpillars are in the rhizomes, also remove and destroy iris leaves in fall to remove any overwintering eggs.

Plant the new divisions in a sunny well-drained spot. Dig an ample size hole leaving a ridge of soil down the center of the hole. Place the rhizome over this ridge with the roots spread out on either side. Plant the rhizome about an inch below the soil surface. Firm the soil over the roots and water thoroughly.

Ready to add iris to your garden? Stop by Phil & Pat Sollars garden at 18814 E 1250 N Rd. in Danville on Sunday, June 12 from 12-5 p.m. during the Vermilion County Master Gardeners garden walk and I will give you a reblooming iris from my garden when you present your garden walk ticket. Supply is limited. While you are in the area, enjoy seven fabulous gardens in Westville. Tickets are $10.00 and available for purchase at Danville Gardens, Berry's Garden Center, Schultz's Nursery, Big R Danville and Tilton along with the Westville Public Library. Check out our website for more information and locations.

Additional University of Illinois Extension Master Gardener Garden Walks:

Saturday June 18, 9am-4pm Champaign County Master Gardeners offer 8 glorious gardens in Champaign, Urbana and Philo and plenty of shopping at Idea Garden in Urbana.

Tickets sold at local garden centers: Country Arbors, Danville Gardens Too, Illini FS Farmtown, Prairie Gardens, Ropp's Flower Factory – Mahomet

Saturday June 25, 9am-1pm Ford-Iroquois County Master Gardeners host exquisite gardens in the Paxton/Loda area with shopping among garden vendors at Majestic Park in Paxton.

Tickets also available at our offices:

Champaign County Extension, 801 N. Country Fair Drive, Champaign PH: 217.333.7672

Vermilion County Extension, 3164 North Vermilion, Danville PH: 217.442.8615

Ford-Iroquois County Extension, 916 W Seminary Ave, Onarga PH: 815.268.4051

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