Answer: Most perennials need to be divided every 3-4 years, but it can vary depending upon the particular plant and how vigorously it grows. Spring is the best time to dig and divide. Plants usually recover quickly because they are all primed to grow. Exceptions abound, however. Irises, for instance, can be dug and divided in the late summer months. This helps them settle in over the fall months and be ready to grow and bloom in the spring. The only rule in digging and dividing is to make sure each division has both roots and tops. As long as each division is an individual plant, it will establish itself when it is replanted. Best wishes with your garden.
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