|When and how does one divide iris?
|Bearded iris clumps should be divided every 3-4 years. Wait about 6 weeks after the plants have finished blooming and dig carefully so you don't damage the rhizomes. A spade works well to lift clumps. Divide by breaking the rhizomes, or cutting them apart. Discard the old center portion and keep the growing ends to replant. Trim the leaves and roots to about six inches and replant after you've amended the soil with organic matter. Plant just under the soil surface, spacing the rhizones 1-2 feet apart. The rhizomes will grow from the ends, so make sure they're pointed in the direction you want the new growth to appear.