Divide Iris Now Here's How

Iris flowers were named for the goddess Iris who is usually represented as a rainbow or as a maiden with a many-colored coat that she uses to create rainbows. And, Iris flowers come in over 250 species, colors and heights. 

Left: throw on the compost pile
Center: Mother and daughter rhizomes
Right: Iris ready to plant

Most garden Iris are the bearded Iris grown from rhizomes that sit near the top of the soil and multiply into webs of mother and daughter bulbs. These old fashioned favorites tolerate almost any soil and conditions.

All Iris have either rhizomes or bulbs where they store food for the next year. Their colonies have to be dug and divided every few years.  

This hot and dry weather is the ideal time to dig and divide rhizomes and bulbs. Start by making a container of 10% bleachwater. Lift a clump of Iris and shake off the dirt. Use clean pruners or a knife to separate them. Trim the leaves to a third of their height. Put old rhizomes on the compost and young ones into the bleach water for 30 minutes to kill insects and diseases. Then put them in the sun to dry for a day. 

In a prepared bed, plant rhizomes on a little mound of soil and drape the roots over the edge. Fill the hole, leaving the rhizome top exposed. 

Siberian Iris have an almost flat flower with a fall that tilts down slightly so they are considered ‘beardless‘. Plant them 2 inches deep in a new location in groups of two to four fans. 

Louisiana Iris and Japanese Iris prefer moist locations.  Plant their bulbs 2-inches deep in well-drained soil in full or part-sun.

Dutch Iris flowers are traditionally either blue, yellow or white, and make excellent cut flowers. They grow from bulbs and want plenty of water in the spring. Plant Dutch Iris bulbs 3 to 4 inches deep. 

All your Iris plantings will reward your efforts next spring filling your garden with color.