How to Divide Overgrown Perennials
When flowers get out of hand, just split them up and make new plants
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.
Dig up the plant
Rake back any mulch covering the base of the stems, then set a spade or shovel 6 to 12 inches from the center of the plant and push it down vertically into the soil. Work the shovel this way around the plant until you've formed a circle. Now slip the shovel blade under the root ball and pry it out of the ground.