Divide To Conquer
If you love bearded iris like I do, you know that, after a few years, they produce fewer and fewer blooms, and may stop blooming altogether. When this happens, it means that the iris has formed a large clump of rhizomes and they need to be divided. Dividing the rhizomes “freshens” the plant, so that it will produce flowers next year and give you several more years of lovely blooms. Digging up the rhizomes also gives you a chance to inspect the rhizomes, removing any that are rotting, diseased or infested with bugs.
Dividing bearded iris is fairly easy. I use a digging fork and push the times of the fork down and a bit toward the rhizome clump (you might need to do this from one to three different angles or sides of the rhizome clump). If you have your irises planted correctly, the rhizomes basically lay atop the soil and are held in place by roots growing from the rhizome. Once you have the clump dug up, inspect it and remove any diseased, rotted or infested sections and with a sharp knife. Then, cut the rhizome clump up into several sections- you will see when you look at the clump where the cuts make the most sense (at the “necks” or thinner parts where the newer rhizomes join the old rhizome). Some people dip the cut rhizome into a 10% bleach solution, claiming it reduces fungal rot, but I never do.
Cut back the foliage to about 2 inches (this is to prevent the plant from toppling over when you replant it and to stop the natural die off of the leaf, which is unsightly). Take each section and plant as you did when you got your first rhizome, with the rhizome atop the soil, roots under the soil. I often take some 1 to 2 foot sticks outside with me when I do this task to help prop the plants upright until the new roots get to grow and anchor the plant into the soil. Water in, check to make sure the soil still covers the roots, but not the rhizomes, and water sparingly over the next few weeks.
One unrelated note: I recently started a full time job that I love and one that is intellectually stimulating, even though it has nothing to do with gardening! I am committed to continuing my gardening (though my fall garden looks a little sad right now, with less attention and this current drought) and to continuing this garden blog, one of the great pleasures of my life!