My iris are overcrowded. When can I divide and transplant them?
Divide iris 6 to 8 weeks after flowering. Cut back the leaves so they’re 6 inches tall, creating a curved fan shape with the remaining foliage. This process makes them easier to handle, reduces water loss and improves their appearance. Use a sharp knife to cut the iris rhizomes, the bulb-like roots, into smaller pieces. There should be at least one fan of leaves per division. Discard old leafless rhizomes or those that appear damaged or insect-infested. Replant rhizome just barely below the soil surface. Plant individually or in groups of three. Face the fan of leaves away from the center of the grouping. Set rhizomes 6 to 24 inches apart with the leaf fans facing outward. Smaller cultivars can be set at the closer spacing and larger, fast growing cultivars should be spaced further apart. Some gardeners plant the rhizomes back to back for quicker fill. Keep in mind the closer your plant the divisions the sooner they will need dividing. Then be patient. The iris divisions may not bloom until the second spring after transplanting.