The Homeowners Column

The Homeowners Column

Time to Divide Peonies

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

September is the month for dividing peonies and most other perennial flowers. All those plants you didn't get moved in the spring now get a second chance to develop wheels. However, peonies are one of the few perennial flowers that survive better with September transplanting than spring planting.

Now as you were reading the paragraph above were you saying pennies, pineys, pea-o'nees and pea'o-nees (my choice). Just say peony and your geographical origin becomes quickly apparent. To help us or to confuse us further, the genus is Paeonia and is pronounced pea-o'ni-ay.

We may not agree on the pronunciation, but peonies are a common Midwestern flower whose popularity grew out of the need for Memorial Day cut flowers. Peony history goes back to cultivation in China over 2,500 years ago. Continued breeding has produced hundreds of cultivars.

Because peonies are so common, we sometimes overlook their beauty. They are hardy, durable, perennial plants with large fragrant flowers.

A complaint I hear periodically about peonies concerns their short bloom period. I treasure them even more for their two-week bloom period. I anticipate the peony buds opening, just as I anticipate the coming of summer. Also selecting early and later season peonies can stretch the flower period to six weeks. Also look for some of the newer cultivars which have stouter, sturdier stems.

Even when not in flower, peonies are a welcome addition massed in flowerbeds. Plant peonies behind spring flowering bulbs such as daffodils or tulips. As the bulb foliage dies, the peony is there to cover the area and the dying bulb foliage. Peonies are great companions to Siberian iris, lilies, iris, phlox, poppies or perennial geranium. The peony foliage is a beautiful background for shorter annual flowers such as red salvia and dusty miller.

When people ask me how often to divide their peonies, I tell them every 150 years without fail. If your daytime calendar doesn't go up that far, just keep in mind peonies do not require regular division for successful blooming the way other perennials such as bearded iris require. Divisions can be done to increase the planting area or if the plants are growing poorly.

Each fleshy root division should have at least 3 to 5 "eyes." The "eyes" actually look more like pink noses and are the shoots for the next season.

The "eyes" should be planted about one to two inches deep. If planted too deeply, the plant will produce foliage and no flowers. Plants should be spaced about 2 to 3 feet apart. Mulch with shredded bark or pine needles in early winter.

Peonies appreciate well-drained soil with an abundance of organic matter. Plants will flower better in full sun, but will tolerate some shade. Light shade will keep some flower colors from fading. Yes, flowers fade in the sun just like blue jeans.

As with many plants this season, peonies have suffered from diseases. Peony measles is a fungal disease that causes purple spots on leaves, stems, flower buds and petals. The disease cannot be stopped this year, but sanitation is very important to control this disease as well as botrytis and phytopthora for next year. Remove and destroy the stems and foliage as soon as they die down this fall. Fungicide sprays in spring can also be used to prevent peony diseases.

Despite what your grandma told you, ants do not help or hurt the peonies. They are attracted to the nectar and it's a great palace to hang out.

Please join us at the Idea Garden on south Lincoln for the fall Saturday workshops at 10:00 am. No fee or registration is required.

September 9
Fall vegetable crops - planting, harvesting and storing.

September 16
Dividing perennials

View Article Archive >>