September is a good time to give attention to peonies and daylilies. Late summer or very early spring is the best time to divide perennials that bloom in spring and summer, letting the plant's energy to go to leaf and root growth. This gives the plants time to let their roots become established before flowering. Generally, divide perennials when they get overcrowded or if you want to increase the plants in your garden.
Most peonies do not need dividing for many years, but they will bloom poorly and should be moved if they get too much shade or become overcrowded. Moving established peony plants is quite simple. First, select and prepare the site. Choose full sunlight and well drained soil. Cut the stems near ground level and carefully dig around and under the plant, with a spading fork if possible. Try to keep as much of the root system as possible. Shake gently to remove loose soil from the root system. Divide the clump into sections using a sharp knife, making sure each division has at least three to five eyes (buds) and a good portion of the root system. Place the plant in the hole you have dug (large enough for the entire root system), so the eyes are one to two inches below the soil surface. Peonies planted deeper than two inches many times fail to bloom well. Fill the hole with soil, firming the soil as you backfill. Water thoroughly. The plants should be spaced about three to four feet apart. Add two to three inches of mulch (straw is an excellent choice). Mulching prevents the freeze and thaw cycle of the soil that can cause damage to the plants. Remove mulch in early spring before growth begins. Your transplanted peony plants probably will not bloom well the first spring. They should be back to full blooming by the third or fourth year.
When dividing daylilies, remember they need five to six hours of sunlight per day and well drained soil to stay healthy. Divide clumps that are three to five years old. Less blooms may be a sign that dividing is necessary. Dig holes and apply organic matter or compost The compost will help the soil to hold moisture between watering. You can place a little bit of bone meal in the hole and put some dirt over it. The bone meal should never directly touch the bulb. Make a small mound in the center of the hole to spread the roots over. When dividing daylilies, look for the individual fans and use a sharp knife to cut between them.
Plant close to the surface. Set the crown no more than one inch below the surface of the soil, just barely covering the rhizome with soil. Pat the soil down around and between roots as you cover the plant. Water thoroughly. Watering is most important to daylilies and they benefit more from water of eight to 10 inches into the soil than from several short, surface watering.
The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange County.