Yard and Garden: Dividing Lilies, Daylilies and Peonies


August 26, 2015, 11:25 am | Richard Jauron, Kendall Evans

AMES, Iowa – Late summer and early fall is a great time to manage the flowers growing around the house and in the garden. The trick is to know the best times and ways to manage particular types of flowers, like lilies, daylilies and peonies. Iowa State University Extension and Outreach horticulturists offer tips on managing different types of flowers during the late summer and early fall.

To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.

When is a good time to dig and divide lilies? 

Early fall is an excellent time to dig and divide Asiatic, Oriental and other garden lilies. Carefully dig up the clump and separate the bulbs. Replant the bulbs immediately. If planting must be Peony Red Bushdelayed, place the bulbs in a plastic bag containing lightly moistened sphagnum peat moss and place the bag in the refrigerator. Plant the large bulbs four to six inches deep. Small bulbs should be planted two to four inches deep. Lilies perform best in well-drained soils in full sun. The large bulbs may bloom the following summer. However, the small bulbs may not bloom for one or two years.

When is the best time to transplant peonies? 

September is the best time to transplant peonies. Begin by cutting the peony stems near ground level. Then carefully dig around and under each plant. Try to retain as much of the root system as possible. 

If desired, large peony clumps can be divided at this time as well. Using a sharp knife, divide the clump into sections. Each division should have three to five buds and a good root system. 

When replanting, dig a hole large enough to accommodate the entire root system of the peony. Position the plant or division in the hole so the buds are one to two inches below the soil surface. Fill the hole with soil and water thoroughly. Peonies perform best in well-drained soils in full sun. 

When can I divide daylilies? 

Daylilies can be divided in early spring, as new growth begins to emerge, or in late summer to early fall. Dig up the entire clump with a spade. Shake or wash off the soil, then carefully pull the clump apart. Often, a sharp knife is necessary to divide large, dense clumps. Each division should have two or three fans of leaves and a good root system. When dividing daylilies in late summer to early fall, cut the foliage back to a height of six to eight inches. 

Replant the divisions as soon as possible. When planting, the daylily’s crown, the area where the shoots and roots meet, should be approximately one inch below the soil surface. Water thoroughly. Divided plants usually don’t bloom well for one or two years.

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