Peonies are cherished garden plants, celebrated for their generous, often fragrant blooms that appear in late spring and early summer. These enduring perennials add beauty to any landscape, with some varieties boasting flowers up to nine inches across. Their popularity stems from their stunning visual appeal and remarkable longevity; established plants can flourish for decades. This resilience and their low maintenance requirements, once established, make them a rewarding addition to many gardens.
Popular Peony Types
Peonies are broadly categorized into three main types, each with distinct growth habits and characteristics, allowing gardeners to choose varieties that best suit their preferences. Herbaceous peonies are perhaps the most recognized type, characterized by soft, non-woody stems that emerge in spring and die back to the ground each winter. These varieties typically grow two to three feet tall and two to four feet wide, producing abundant blooms from late spring into early summer.
Tree peonies, in contrast, are woody shrubs with stems that persist above ground throughout the year, forming a permanent framework. They can reach heights of three to seven feet, offering larger, often dinner-plate-sized, flowers that appear earlier in the spring than herbaceous types. While their woody structure provides year-round interest, their bloom period is typically shorter than herbaceous varieties.
Itoh peonies, also known as Intersectional peonies, represent a hybrid cross between herbaceous and tree peonies, combining desirable traits from both. These plants feature the sturdy, large blooms and unique color range of tree peonies, yet their foliage dies back to the ground in winter like herbaceous varieties. Itoh peonies boast strong stems that usually do not require staking and can grow up to three feet tall and wide, often providing a longer blooming season and attractive foliage that lasts well into the growing season.
Planting Peonies
Proper planting is crucial for a peony’s long-term health and blooming potential. Peonies thrive in full sun, ideally receiving at least six to eight hours of direct sunlight daily. In warmer climates, afternoon shade can protect flowers and prolong their bloom. Good air circulation also helps prevent fungal diseases.
Peonies prefer deep, fertile, well-drained soil with a slightly acidic to neutral pH (6.5-7.0). Amend heavy clay or very sandy soil with organic matter like compost to improve drainage and fertility. For heavy clay, planting in raised beds can also enhance drainage.
The ideal time to plant peonies is in the fall, typically late September to October, or later in warmer zones. This allows roots to establish before ground freeze, supporting strong spring growth. While spring planting is possible, fall-planted peonies establish more effectively and may bloom sooner.
Proper planting depth is crucial, especially for herbaceous peonies, as planting too deep inhibits blooms. Plant herbaceous peonies with the “eyes” (buds on the root) one to two inches below the soil surface. For tree peonies, plant the graft union four to six inches deep to encourage root formation. Space plants three to four feet apart for mature size and air circulation. After planting, water thoroughly to settle the soil.
Caring for Peonies
Ongoing care helps established peonies maintain vigor and produce abundant blooms. Consistent watering benefits plants during dry periods, especially in the first year after planting. While established peonies are drought-tolerant, they benefit from deep watering every 10-14 days during dry spells, aiming for about one inch per week. Direct water to the plant’s base to avoid splashing foliage, which can encourage fungal diseases.
Peonies do not typically require heavy feeding once established, especially if the soil was properly amended at planting. An annual side-dressing of one inch of compost or aged manure in spring can provide sufficient nutrients. Over-fertilizing, particularly with high-nitrogen fertilizers, can promote lush foliage at the expense of flowers and may make plants more susceptible to disease.
Many herbaceous peony varieties, especially those with large blooms, benefit from structural support to prevent flopping. Place peony rings or stakes early in the growing season. Mulching around the base, particularly for new plants or in colder climates, conserves soil moisture, regulates temperature, and suppresses weeds. Keep mulch away from the crown to prevent rot and ensure bud formation.
Pruning and Maintenance
Pruning and seasonal maintenance contribute to peony health and aesthetic appeal. Deadheading spent peony blooms prevents the plant from expending energy on seed production, directing resources towards root development and future blooms. For herbaceous and Itoh peonies, deadhead individual spent flowers throughout the blooming season.
For herbaceous peonies, cut stems back to ground level once foliage yellows and dies back, typically after the first hard frost. This removes potential overwintering sites for diseases and pests, promoting healthier new spring growth. Discard all cut foliage, do not compost, to minimize disease transmission.
Tree peonies, with woody stems, do not require annual cutback. Maintenance involves removing dead or damaged stems in late winter or early spring. Winter protection, such as mulching the base and wrapping lower stems with burlap, benefits young tree peonies or those in colder climates. Promptly remove any diseased foliage to prevent fungal spread.
Troubleshooting Peony Problems
While generally resilient, peonies can encounter issues with pests, diseases, or blooming. Botrytis blight (gray mold) is common, especially in damp conditions. Symptoms include brown or black spots on leaves, wilting stems, and buds that blacken and fail to open, often covered in fuzzy gray mold. Manage by removing affected parts, improving air circulation, and avoiding overhead watering.
Powdery mildew appears as a white or grayish coating on leaves and stems, thriving in humid environments. While not fatal, it can make the plant unsightly. Increase air circulation, avoid overhead watering, and prune affected areas.
Root rot, characterized by yellowing leaves, weak growth, and a foul smell, indicates overly wet soil. Ensure well-drained soil and water deeply but infrequently to prevent this.
Common peony pests are generally not severe. Ants are often seen on buds, attracted to sugary sap, but are harmless. Thrips can cause distorted buds and discolored petals; monitor their presence by shaking stems over a light surface. Mealybugs, appearing as tiny white cotton-like masses, can cause yellowing or deformed leaves and are treated with insecticidal soap or neem oil.
A lack of blooms can be frustrating. Immature plants may not bloom for one to two years, requiring patience as they establish. Transplant shock can also temporarily halt blooming; a recently moved peony may take a season or two to recover.