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Home  >  Perennials and Grasses  >  Selection, Culture and Care  >  When and how should I divide my daylilies?

When and how should I divide my daylilies?

After flowering and with the onset of 90 degree weather, daylilies may look weak and become slightly yellowed. This is the time that you really notice the effects of an overgrown bed. As clumps get old, the center will no longer produce leaves and flowers and the bed begins to look a little thinned out. In the process of renovation, these old and unproductive parts should be cut out. Renovation is best done in early to mid-August.

About a day before digging the plants, water an otherwise dry bed and cut the tops back to about half height. Next, begin prying the clumps out of the soil. It is helpful to use a four-tined spading fork for this operation. The fork is easy on the root system because it loosens the soil first, whereas a shovel will tear the roots apart unless you take special care in digging. Gently lift the plants out of the soil and lay to one side.

Once the plants are dug, the soil can be improved by adding compost or spaghnum peat moss and sand or expanded clay, mixing with the soil in a ratio of one third each in the top 6 to 8 inches. Next, hose the plants down to remove some of the soil from the tuberous root system.

Division is easy, especially if you use two spading forks. Insert the forks into the center of a clump so that they touch back-to-back and force the clump apart by leveraging the forks against each other. One clump may be divided several times until you have two to perhaps four smaller bunches. Within each bunch there should be about 2 to 3 green, leafy shoots. These are then replanted in the prepared bed either in rows with the plants spaced 16 to 18 inches apart, or in groups of 2 to 3 clumps each with 24-inch spacings between the groups. There is no real trick to setting the plants back into the bed except to plant no more than 1 inch below the surface of the soil. Planting deeper may retard and reduce flower production next year.

Daylilies need about 6 to 8 weeks to develop a new root system. This growth should be completed before the first frost which is expected as early as October 15. While there are many hardy daylilies available that survive temperatures below freezing, plants should be mulched with 2 to 3 inches of bark, composted leaves or other organic material. In the Spring, lightly feed the daylilies with a complete fertilizer that is low in nitrogen.