Answer: The blooms of iris can become stunted when the plants are overcrowded. If not divided, they will eventually stop blooming altogether. Wait until late August, then dig the rhizomes, divide them, and then replant. After removing the iris from the bed, amend the soil with compost or other organic matter. Then cut the leaves and roots back to about 6" (for easier handling). Divide the rhizomes by cutting both ends away from the center. The center is the oldest part and can be discarded. Replant the ends, placing the rhizomes so that they are just barely below the surface of the soil. Then water well. The iris should produce larger flowering stalks next spring.
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