How to Divide Overgrown Perennials

Q: When is the best time to divide overgrown perennials and make new plants from them? —Maria-Teresa Turner, Leesburg, VA.

Roger Cook replies: Dividing perennials every three to six years is a great way to thin clump-forming varieties, like the daylily shown here (Hemerocallis), which blooms from late spring to late summer. This technique can also be used to control plant size, invigorate growth, and multiply the number of specimens in a garden.

A good rule of thumb is to split apart spring- and summer-blooming perennials in late summer or before the fall frost. Fall bloomers are best divided in the spring so that they can devote their energy to growing roots and leaves.

Before dividing, water the mother plant well for a day or two before you dig it up, and wait for a cloudy day to do the actual digging—hot, sunny weather stresses plants. Then follow these steps and you'll be rewarded with new, more vigorous plants to share with friends or add to your garden.

Pictured: Landscaper Randy Leland of Groundworks Landscaping cradles the root ball of a daylily that's ready to be divided.

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Helpful Info

Step By Step: How to Propagate Fall Perennials into Spring Plants

Gallery: 7 Fall-Blooming Perennials

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