Answer: Plants are best divided in the early fall, just as they're finished for the season, or early spring, just as they're beginning to grow. Disturbing the roots in the winter can have serious effects. Usually winter soils are cold and clammy and tend to hold tight to roots. If you tug and pull, you could damage or sever important roots. Wait until early spring when soils warm up and dry out a bit, then dig, divide and transplant your perennials.
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