Peonies, with their large, often fragrant blooms, are beloved perennials that bring classic beauty to gardens. Their enduring nature and impressive floral displays make them widely appealing.
Understanding Peony Types
Peonies are broadly categorized into three main types, each with distinct growth habits. Herbaceous peonies, the most common variety, die back to the ground each winter, emerging anew in spring. They typically grow to about 3 feet tall, producing abundant flowers from late spring to early summer.
Tree peonies feature woody stems that remain above ground year-round, forming a shrub-like structure. They can reach 5 to 7 feet, with large blooms appearing earlier, often by mid-May. Itoh or Intersectional peonies, a hybrid, combine characteristics of both. They have sturdy, self-supporting stems like tree peonies but die back to the ground in colder months like herbaceous varieties.
Planting Peonies for Success
Proper planting ensures healthy, blooming peonies. The ideal time to plant is in the fall, several weeks before the ground freezes, allowing roots to establish before winter.
Peonies thrive in full sun, requiring at least six to eight hours of direct sunlight daily for optimal flowering; some afternoon shade can be beneficial in warmer climates. Well-draining, fertile soil with a slightly acidic to neutral pH (6.5-7.0) is important. Amending heavy clay soils with compost improves drainage.
When planting bare-root peonies, position the root so the “eyes” or buds are no more than 1 to 2 inches below the soil surface. Planting too deeply often causes a lack of blooms. Space plants 3 to 4 feet apart for good air circulation, which helps prevent disease. After planting, water thoroughly to settle the soil.
Essential Peony Care
Consistent care helps peonies thrive and produce abundant blooms. Young plants need about an inch of water per week, while established peonies benefit from deep watering every 10 to 14 days, especially during dry periods. Avoid overhead watering to reduce fungal disease risk.
Peonies do not require heavy fertilization; working compost into the soil at planting is often sufficient. If soil is poor, a light application of balanced fertilizer in early spring can help, but avoid excessive nitrogen which inhibits blooming.
Large, heavy blooms, particularly “bomb” flower forms, can cause stems to flop, especially after rain. Providing support, such as a peony cage or stakes, early in spring helps prevent this. Deadheading spent flowers improves appearance, but allowing foliage to remain until fall is important for energy storage for next year’s blooms. For herbaceous peonies, cut back foliage to ground level after the first hard frost to prevent overwintering diseases.
Addressing Common Peony Issues
Several factors can cause peonies not to bloom. Incorrect planting depth, where “eyes” are buried too deeply, is a frequent culprit, leading to lush foliage but few or no flowers. Insufficient sunlight (less than six hours a day) can also reduce bloom production. Peonies need cold temperatures during winter to form buds, so lack of chilling hours in warmer climates can prevent flowering.
Ants are often seen on peony buds, attracted to sugary sap, but they are harmless and not necessary for buds to open.
Botrytis blight, a common fungal disease, causes young shoots to rot, buds to blacken and fail to open, and leaves to develop brown blotches. This disease thrives in cool, wet conditions. To manage botrytis, remove and destroy infected plant parts, ensure good air circulation by proper spacing, and avoid overhead watering. Cutting back herbaceous peonies in fall also reduces disease overwintering.