Around Memorial Day each year you see many colorful clumps of showy peonies in farmyards and gardens. Some of them give off an intoxicating sweet fragrance second only to tea roses. Newer varieties have exotic flower forms but perhaps a less powerful fragrance.
Peonies grow and flower best in full sun, but will still do well with light afternoon shade. They like some organic material and compost in the planting hole to do their best. They should be planted away from large trees or shrubs, and if they are in the middle of the lawn you should maintain a mulch circle around then so that lawn grasses don’t steal their food and water, resulting in smaller flowers.
The most important thing to know when planting peonies is not to plant them too deep. The “eyes” (small points where the new plants will sprout each year) should be almost at the surface when you’re finished or they will grow but not bloom. You should loosen the planting soil in an area three feet wide, work in compost and bone meal-based fertilizer (Espoma Bulb Tone is our favorite) a foot deep, and then set the plants near the surface on top of the loosened soil. Pine nugget mulch will keep the weeds out and not smother the tubers.
Peonies should be fed in early spring and again after they bloom. Avoid high nitrogen fertilizers like Miracle-Gro; too much nitrogen will give you great foliage but not much bloom (and weak, floppy stems). The best food for peonies is bone meal and potash; that’s why we use Espoma Bulb-Tone.
If you remove the flowers as soon as they fade, you’ll get better bloom next year because setting seed reduces next years’ bloom. When the leaves turn brown, cut the stems back to three inches and discard them. During the dry summer months, Peonies need regular, deep watering. Mulching with pine bark or composted mulch will help keep the soil cool and moist, and control weeds.
Healthy Peonies should only be divided every ten or fifteen years. They don’t like to be disturbed, but occasional thinning will help them in the long term. Their roots become old and woody, and infested with borers that eat them hollow from the inside. If you dig them up, untangle them and cut away the old woody tubers, they will reward you with better flowering once they recover. You’ll also have lots of extra peony plants to spread around your garden or share with friends.
Gently cut or pull apart the roots into sections, making sure there at least 3 or 4 growth eyes in each new section. Trim away rotten spots with a sharp, clean knife. Dust the cut surfaces with garden sulfur to discourage disease infection and rot. Prepare a new home for them by working humus and Bulb Tone into the soil one foot deep, and re-set the plants shallowly in the loosened soil.
Ants on peonies are a totally normal, natural and temporary thing. Peonies produce small amounts of nectar, supposedly to attract ants to help opening their flower buds. Do not try to get rid of the ants on your peonies. Since the ants are harmless, there’s no reason to threaten helpful insects or birds with chemicals.
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers”. “Let’s Grow” is published weekly; column archives are on the “Garden Advice” page at www.goodseedfarm.com. For more information is available at www.goodseedfarm.com or call GoodSeed Farm Landscapes at (937) 587-7021.