Peonies are treasured garden plants, known for their fragrant blooms and remarkable longevity. These resilient perennials can flourish for decades, becoming a lasting feature in a landscape. Their dramatic flowers, which can reach up to nine inches across, signal late spring to early summer, bringing color and elegance to any garden. Once established, their low-maintenance nature provides abundant beauty year after year.
Understanding Peony Types
Peonies are broadly categorized into three main types, each with distinct growth habits. Herbaceous peonies are the most common, with soft stems that die back to the ground each winter. They typically grow two to three feet tall and wide, blooming from late spring to early summer.
Tree peonies form woody stems that remain above ground year-round, resembling small shrubs. Some varieties can grow up to seven feet tall, offering large, often earlier blooms in shades not typically found in herbaceous types.
Intersectional (Itoh) peonies are hybrids combining traits from both herbaceous and tree peonies. They feature sturdy stems that die back in winter like herbaceous types but produce large, vibrant flowers. These hybrids offer a longer blooming season and typically do not require staking.
Planting Peonies Successfully
Proper timing and location are fundamental for successful peony planting. The optimal time is fall, several weeks before the ground freezes, allowing roots to establish. While spring planting is possible, fall-planted peonies generally establish more robustly.
Peonies thrive in full sun, requiring at least six to eight hours of direct sunlight daily for abundant blooms. In warmer climates, afternoon shade can protect flowers from intense heat.
Well-drained, fertile soil with a slightly acidic to neutral pH (6.5-7.0) is important. Amend heavy clay soils with compost to improve drainage.
For bare-root herbaceous peonies, plant the “eyes” (growth buds) one to two inches below the soil surface; planting too deeply causes poor blooming. For tree peonies, plant the graft union four to six inches below the soil line to encourage its own root system. Space herbaceous peonies three to four feet apart for good air circulation, preventing fungal diseases.
Peony Care Essentials
Consistent care helps peonies thrive and bloom abundantly. Peonies need regular watering, especially during dry spells and their first year (one to two inches per week). Once established, they are more drought-tolerant, but deep watering every ten to fourteen days during dry periods benefits mature plants. Water at the base to avoid wetting foliage, which can encourage fungal issues.
Fertilize judiciously; too much nitrogen promotes foliage over flowers. Apply a light, low-nitrogen fertilizer (e.g., 5-10-10) in early spring as shoots emerge and again after blooming. A second feeding in late summer or early fall can support root development. Organic amendments like compost or bone meal also enrich soil.
Peonies require a chilling period of at least six weeks with temperatures below 40°F (4°C) during winter to set buds. This cold requirement explains why they perform best in USDA Zones 3 through 8.
After blooms fade, deadhead spent flowers by cutting the stalk just above a leaf. Allow foliage to remain through summer for photosynthesis, building energy for next year’s flowering. Cut back herbaceous peony stems to a few inches above ground after the first hard frost or when foliage yellows in fall.
Addressing Common Peony Problems
Peonies are generally resilient but can have common issues. Lack of blooms often stems from incorrect planting depth (eyes too deep), insufficient sunlight (less than six hours daily), or late spring frosts. Newly planted peonies may also take a year or two to establish before blooming.
Fungal diseases like botrytis blight (grey mold) can cause wilting stems and browning buds. Good air circulation and avoiding overhead watering help prevent these issues. Remove and dispose of infected plant parts to manage disease spread.
Ants on peony buds are common and harmless; they are attracted to sugary nectar and do not impact plant health or blooming. This natural phenomenon is often observed and is not a cause for concern.
Propagating Peonies
Division is the primary method for propagating herbaceous peonies, rejuvenating older plants and creating new ones. The optimal time for dividing is fall (late summer through September), after foliage dies back and red “eyes” are visible at the base.
To divide, cut foliage to ground level, then carefully dig around the root system (about twelve inches from the center) to avoid damaging brittle roots. Wash off soil to expose eyes. Use a sharp knife to divide the clump into sections, ensuring each has at least three to five eyes and healthy roots. Divisions with fewer eyes may take longer to bloom. Replant immediately, ensuring eyes are one to two inches below the soil surface, similar to initial planting.
Tree peonies are typically propagated by grafting or cuttings, a more complex process for home gardeners. This method is generally undertaken by experienced cultivators rather than casual enthusiasts.