By Julie Christensen
Peonies (Paeonia) have an ancient history, dating back over 4,000 years to China where they were first cultivated. Myth says that the Greek physician to the Gods, Paian, gave peonies their name and used the roots and seeds to heal Hades, God of the Underworld, who had been wounded in battle.
During the Middle Ages, herbalists used the plant to treat labor pains, headaches, bladder stones, nightmares, epilepsy and lunacy. The plant was said to ward off evil spirits, and was often grown along pathways and entryways for this purpose.
Peony flowers, along with lilacs and roses, were a favorite of early settlers and pioneers, mainly because of their beauty and hardiness. The delicate, fragrant flowers belie the plants’ longevity and durability. These are true workhorses in the garden. Peonies can live – and bloom – for 50 to 100 years, and are hardy in U.S. Department of Agriculture plant hardiness zones 2 through 8. Their cold hardiness, in particular, allows them to grow where many plants fail.
Growing and Caring for Peonies
Peonies grow best in full sun, although they’ll bloom in partial shade. They need rich, well-draining soil with a soil pH between 6.5 and 7.5 – a boon for gardeners with alkaline soil. Plant peonies in spring from nursery transplants or divisions. Dig a hole for each plant that’s 1 foot deep and wide. Amend the soil with compost, manure and ¼ cup 5-10-5 fertilizer. Space dwarf peonies 2 feet apart; give standard peonies 3 feet of space. When planting peonies, make sure that the eyes – which are the pink buds on the roots – are planted only 1 inch beneath the soil surface. A common error is to plant peonies too deeply, which will delay or prevent blooming.
Water peony flowers well immediately after planting and keep the soil evenly moist as the roots become established. Peonies may take two or three years to begin blooming, depending on the size of the division. Larger plants bloom earlier.
Mulch peonies with 2 inches of wood chip mulch, especially if you live in an area with cold winter climates. Stake tall plants so they don’t break in the wind and remove spent flowers to prevent fruit formation. If you allow the fruit to form, the plants won’t bloom as well in subsequent years.
Fertilize established peonies each spring with ¼ cup 10-10-10 fertilizer, sprinkled judiciously over the soil. Keep the fertilizer at least 6 inches from the plants’ crowns and leaves. Divide the plants in the fall every 5 to 10 years, or when flowering slows. Cut the plants’ foliage back to 4 inches. Dig the plants up carefully and wash the soil off the roots so you can see the pink eyes. Cut the plants with a sharp knife and replant them. Again, be careful not to plant them too deeply.
Potential Pests and Problems
Peonies are generally pest and disease resistant, but they are prone to fungal diseases, especially botrytis blight. This disease is most prevalent after a wet, cool spring and causes blackened spots on the leaves, soft decaying roots and stems, and flowers that fail to open or turn black. Remove diseased plant material immediately and clean up the area in the fall. Apply a fungicide labeled for botrytis blight in the spring.
Ants appreciate the nectar from peony flowers, but they don’t cause any damage to the plants. The only real insect pest of peonies is scale. You may notice patches of bumpy areas on the stems of the plant that are actually colonies of insects. These insects have piercing mouth parts that suck the juices from the plants, causing wilting and slow decline. Treat scale in early summer with insecticidal oil or soap.
Peonies sometimes fail to bloom. The most common reason is planting them too deeply, but excess nitrogen, inadequate sunlight, overcrowding, late freezes, inadequate phosphorus, or inadequate potassium may also be culprits.
Varieties to Try
Peonies generally come in three forms: herbaceous peonies, which die back every year; tree peonies, which have a woody stem; and intersectional peonies which are a hybrid cross between herbaceous and tree peonies. Peonies range in height from 2 to 4 feet tall and produce flowers labeled double, semi-double, single, anemone or Japanese. Peonies bloom for only a week or two, so plant several varieties with staggered bloom times to extend the season.
- ‘Bowl of Beauty’ is an early bloomer that produces rosy pink flowers.
- ‘Krinkled White’ blooms mid-season with prolific white flowers.
- ‘President Lincoln’ produces deep red flowers in late summer.
For more information on peonies, visit the following links:
Growing Garden Peonies from Iowa State University Extension
Peonies from Clemson Cooperative Extension