Answer: Iris grows from rhizomes that are best divided every 3-4 years, in late summer (usually August). The rhizomes will be fine if left in the ground over the winter. You can spread some organic mulch over the area to help suppress weeds during the winter months. When digging and dividing, wait until the flowers have faded and cut back the flowering stems. Then dig carefully so as not to injure the rhizomes. You can cut the roots back to about 6 inches, and the fan of leaves back about 6 inches, as well. To divide, break or cut the ends of the rhizome off, discard the old center portion, and replant the ends. Place them just barely below the surface of the soil and water them in well. Your iris will become established over the winter and will begin to produce foliage and flowers as soon as the weather warms in the spring.
Q&A Library Searching Tips