The Bay Gardener
By Dr. Frank Gouin
Garden Math: Divide and Multiply Daylilies
Get more blooms next year by transplanting
When daylilies become so dense that their centers begin to die, it’s time to dig, divide and transplant. Now is the best time of year to split daylilies, just as the daylilies finish flowering. Dig and divide daylilies at five- to six-year intervals to keep your planting healthy and uncrowded.
Daylilies have very coarse and fleshy roots so usually the soil quickly falls away without much shaking. Daylilies also produce tuber-like appendages, like those of dahlias and sweet potato roots. With daylilies, however, these appendages are water and nutrient storage organs, and the plants can be transplanted without them.
If the soil in your garden is clay or silt loam, you will find that most of the daylily roots will be shallow and extend a foot or more away from each plant. If the soil is sandy, you will find most of the daylily roots deep and directly below each plant. So if your soil is a clay or silt loam, start digging at least 12 inches away from each clump. For digging daylilies, I prefer using a garden spade to a shovel to minimize root damage. The garden spade also allows you to shake the soil more easily from the roots as you lift the clump from the ground.
Divide daylilies by pulling their crowns apart with your hands. If the fleshy roots are heavily twisted together, cut them with a Japanese gardeners knife or serrated kitchen knife, which you should dedicate for only horticultural use.
To prevent early over-crowding, divide the clumps into individual plants and store them in wet burlap or wet newspapers until they are ready to transplant. The roots will dry out under the hot sun and recover slowly.
Daylilies will grow in almost any well-drained soil, performing best when planted in a soil rich in compost, especially before the first winter following transplanting. Don’t hesitate to spade a couple inches of compost into the soil before planting. They will also grow in a wide range of soil pH.
Daylilies can grow and flower in partial shade, but they become fullest when grown in full sun.
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