Peonies are a perennial favorite in my flower garden and the official flower for the State of Indiana. They are easy to grow and reward me every year with beautiful, fragrant flowers.
Peonies like a sunny location where their roots can spread out in well-drained soil with a pH range of 6.5 to 7.5. Give them some room as they do not like to be crowded. Planting, transplanting and dividing is best done in early fall, say about September. It can also be done in the spring as soon as the ground can be worked. Dig a large hole and work some aged organic matter into the bottom of it. Place the peony roots into the hole and spread them out, keeping the eyes (small red buds) one to two inches below the surface of the soil. Water well.
In the spring, when the shoots have reached about three inches, you should place some supports around the plants. Peonies grow anywhere from two to four feet tall and the blossoms can be quite heavy. Without support, the beautiful flowers will droop to the ground or will be knocked over by rain or wind. After the flowers are spent, cut the stem back deep into the foliage. Unfortunately, the flowers only last about a week. They do hold up well as cut flowers, so I always make a point of cutting some to bring into the house. And I might also add that their wonderful fragrance easily fills a room.
When peonies fail to flower well it can be an indication that the plant needs to be divided. Lift the clump and wash away the soil to reveal the eyes. Use a sharp tool to carefully divide the peony into several smaller clumps, each having three to five eyes and a fair amount of roots. Replant immediately. Peonies can be a bit finicky about being transplanted. Plant them at exactly the same depth in their new location as their old one to reduce the shock of being uprooted. When planting anything I like to use a root stimulator in my water. This is a product that when added to the water at time of planting gives the root system a boost. It can be found at most nurseries and garden centers.
Peonies do not have many pests or problems. There are two fungal diseases that rear their ugly heads now and then. One is botrytis blight and the other is leaf blotch. Botrytis affects leaves, stems and flowers and occurs during wet springs. Stems may soften and decay, spots appear on leaves and the flower buds will either rot or blacken and will not open. Leaf blotch develops during moist, warm weather with glossy, dark purple spots appearing on the leaves. Both funguses can be controlled by removing the affected plant parts and applying a fungicide labeled for such a disease and avoiding overhead watering.
The only insect pest to mention when it comes to the peony is scales. These will appear on stalks and leaf bases late in the summer and will overwinter on the stalks below the soil. To control scales, remove the plant material in the fall, then apply an insecticide labeled for such in late May to mid-June the following year. Ants on peony flowers are just attracted to the sugary liquid secreted by the buds and are doing no harm.
As always, Happy Gardening!
The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange County.