The garden peony is a popular, long-lived perennial that provides beautiful flowers in spring and handsome foliage throughout the growing season. If left undisturbed, a peony plant may flower for 50 or more years. Below is information on growing peonies in Iowa, including care, propagation, planting, types, and recommended cultivars.
Several different peony species and hybrids are ideally suited for Midwestern landscapes. Each are wonderful potential additions to the landscape. The most common peony is the herbaceous peony, sometimes referred to as the garden peony. These peonies are either selections or crosses of Paeonia lactiflora, P. officinalis, P. japonica, or any of about 26 other species. Most garden peonies grow 2 to 3 feet tall. Mature plants may be 3 to 5 feet wide. Peonies bear 3- to 6-inch-diameter, fragrant flowers in May or early June. Flower colors include white, pale yellow, pink, rose, and red.
In addition to the classic herbaceous peony, several other types of peonies can be successfully grown in Iowa. They include Fern-leaf peonies (Paeonia tenuifolia), Tree peonies (Paeonia suffruticosa), and Intersectional or Itoh hybrids (crosses between herbaceous and tree peonies).
Learn more about the different types of peonies in this article: Peony Types and Cultivars for Iowa.
Grow peonies in well-drained soils and full sun for best flowering. Plants need at least six hours of direct sunlight per day and a location with good air movement helps prevent foliar disease problems. Do not plant peonies near trees or large shrubs. The shade cast by the trees and shrubs, together with the competition for water and nutrients, will discourage plant growth and flowering. Root rots may be a problem in wet, poorly drained soils. Poorly drained soils can often be improved by incorporating compost into the soil.
Plants are beautiful in spring but hold little other interest throughout the year, except for some marginal yellow fall color. For this reason, place in the perennial border where the flowers can be appreciated in spring and the dark green foliage can be used as a backdrop for other plants the rest of the year.
Common peonies prefer shallow planting depths. When planting bare-root plants in the spring, position the buds 1-2 inches below the soil surface. Plants that are planted too deeply do not bloom well. Container-grown peonies are generally planted at the proper depth, so transplant them to a similar depth in the landscape. After planting, water well the first year to establish a good root system.
Peonies may not bloom the first spring. In fact, it is advisable to remove flower buds that develop the first spring to promote root and foliar growth. While the plant may produce only a few blooms by the second year, flower numbers should increase rapidly by the third and fourth years. Once completely established, full flower production should continue for many years.
Fertilize plants in early spring as the new shoots begin to emerge from the ground. One-fourth cup of 10-10-10 fertilizer should be lightly cultivated into the soil around the crown of the plants. Avoid getting fertilizer within 6 inches of the crown. Peony crowns and young shoots are very susceptible to fertilizer burn. Water the area immediately after the fertilizer application to dissolve the fertilizer and move the nutrients into the soil.
Many peonies, especially the double-flowered varieties, must be staked/supported to prevent them from flopping over when in bloom. The best way to support peony plants is to place metal hoops or rings over the plants in early spring. The flowers of single-flowered and Japanese varieties are lighter in weight and less likely to flop over when in bloom.
Cultivate around plants to control weeds and break hard soil surfaces that may slow water penetration to the roots. Do not cultivate deeper than 1 to 2 inches to avoid damaging the root systems of the peonies.
Water peonies when the weather is dry. This is extremely important during bud formation and flowering. Buds may fail to enlarge and open if the plants are dry. Water by thoroughly soaking the soil to a depth of 12 inches.
Remove the spent flowers (deadhead) to improve the plant's appearance and prevent fruit formation. Fruit development reduces the amount of food the plant is able to store in its root system and may result in fewer flowers the following spring.
After a hard freeze in the fall, cut off the foliage at ground level and discard the plant debris. Removal of the peony foliage from the garden helps to control leaf blotch and other fungal diseases.
Peonies can be left undisturbed in the garden for many years. Occasionally, however, it becomes necessary to move plants. Peonies in partial shade need to be moved to a sunny location to improve flowering. When redesigning a perennial bed or border, plants may need to be moved to a different location. Large, vigorous peonies can be dug and divided for propagation purposes.
The best time to divide and plant peonies in Iowa is September.
Learn more about transplanting and dividing peonies in this article: Transplanting and Dividing Peonies.
Peonies are easy-to-grow, long-lived, and reliable performers in the garden. But they occasionally have issues. More detail on the most common issues with peonies are in this article: How to Manage Potential Problems Growing Peonies.
- How and where can I buy peony plants?
- How and where do I plant peonies?
- How can I prevent my peonies from flopping?
- When can I cut back peony foliage?
- What is the proper way to divide peonies?
- Is it necessary to periodically divide peonies?
- Are ants necessary for peonies to flower?
- Flower buds form on my peonies, but don't open. Why?
- In spring, some of the flower buds on my peonies turn brown and fail to open. Why?
- What is wrong with my peony leaves?
- There are large, brown spots on my peony leaves. What should I do?
- How can I best harvest and preserve my peony flowers for cut flowers?