Answer: Iris can fail to bloom if they are overcrowded. Digging and transplanting is generally done in mid- to late-August. At that time, cut the foliage down by two-thirds so you have a fan-shape. Then dig and divide, breaking the rhizomes into pieces so that each piece has a fan of leaves. Usually the middle of the rhizome will not have leaves attached and can be discarded. When replanting, give each division at least 6" all around for room to grow.
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