Carole Howell is a freelance writer from Lincolnton, N.C.

This article applies to:



Taking Care of Irises
by Carole Howell       #Flowers   #Ornamentals

Sometimes called the poor man’s orchid, the bearded iris, with its myriad of colors, puts a new box of crayons to shame. These diverse, drought-resistant garden beauties provide an elegant centerpiece for many Southern gardens, with their magnificent spring blooms. But the plants are great in the garden even after the blooms have faded, thanks to their lush green stalks.

While spring is when we usually think of irises, now is actually the time when work needs to be done to ensure a beautiful flowering next season. Shirley Spoon Knox of Lawndale, N.C., is well known for her beautiful irises and loves to share her knowledge, much of it passed along from her mother. Knox recommends dividing irises every four to five years, even if you don’t plan to replant them. July, August and September, when irises are dormant, are the prime months for dividing them to ensure a brilliant spring with multiple blooms. Without regular division, the clump of irises will bloom less and not thrive.

The root of an iris is called a rhizome. From year to year, the primary rhizome grows several increases of younger, fresher rhizomes that encircle the mother rhizome. These are what you will divide and can replant in your own garden or share with friends and neighbors.

The best time to divide is early in the morning before the sun gets fierce. To divide a whole clump, insert a wide garden fork about 6 inches from the perimeter of the circle and lift the clump to the side.

As you trace the rhizome with your finger, you will feel a small indention that indicates the node’s connection to the mother plant. You can easily snap off the rhizomes or use a sharp knife to slice the node from the mother plant and lay it aside. If you use a knife, some experts advise dipping it in a diluted mixture of chlorine bleach: 10 parts water to 1 part bleach. Don’t forget to label your rhizomes, at least by color and height and possibly by cultivar name.

Wash off excess soil and soak the rhizomes for 10 minutes in a 10:1 water-chlorine solution and then rinse in a clear water bath. Air dry for 30 minutes in the shade. Choose the plumpest, healthiest ones for replanting, inspecting them for signs of disease or rot, or damage by borers.

Some gardeners trim the leaf fan and roots so they’re easier to handle and replant. Knox recommends leaving both intact in order to give the new plant a good start in its new setting. She does, however, snip off any brown tips or damaged leaves.

Lilla Spoon’s Fertilizer Recipe 

5 gallons of dry sphagnum peat moss
3-4 shovels of Black Cow compost
1 quart powdered dolomitic lime
1 pint wettable sulphur (discourages fungus and insects)
1 ½ quarts Triple Super Phosphate (for blooms)
1 quart 10-10-10 fertilizer

Knox likes to replant her irises the same day in a previously prepared raised bed, 2-3 inches deep and wide enough to accept the roots. Irises prefer morning and midday sun and well-drained soil. To prepare her soil for planting, Knox swears by the soil and fertilizer recipe passed down to her from her mother (see sidebar). She mixes ½ cup into the hole and then waters it in.

“Irises don’t like crowds,” Knox says, which is one reason why they need to be divided. When planting, place them 18-25 inches apart. Place the rhizome straight down, spreading the roots around. The top third of the horizontal part of the rhizome should rise slightly above the soil line. Cover with soil and pack it firmly with your hand. Scratch in another ½ cup of soil mixture around the plant. Water once more and continue to water lightly for the next two weeks if the weather is dry.

Irises should be lightly fertilized twice a year with a 10-10-10 fertilizer. Do this once in March, just before blooming, and again in June, just after blooming has finished. Reblooming iris, which can bloom up to four times a year, should get an extra dose of fertilizer in August, as well as plenty of water.

Weeds are always a problem for gardeners, and you will find them in your irises since weeds like fertilizer too. Knox not only pulls weeds regularly, but she also plants phlox, thrift, herbs and lilies among her irises to keep the beds colorful long after the iris blooms have faded.

“Irises feed the human desire to create, perpetuate and inspire beauty,” Knox says. Caring for them draws us out to the sunshine and fresh air and provides us with the feel of soil and water as well as the healing power of exercise. Sharing them gives us the opportunity to meet with old friends and cultivate new ones. Irises are truly a grounding influence for our souls … no pun intended.

Photos courtesy of Carole Howell


Posted: 08/23/13   RSS | Print


Share this story on:
Facebook       Twitter            

Other People Are Reading