How to Grow Peonies
By: Julie Day
Peonies (or Paeonies) add a splash of luxury to the perennial garden, literally drooping with late spring blossoms amid lush, dark-green foliage. The blossoms are among the showiest of all perennials, fragrant and excellent in bouquets. Once established, these plants put on a show for decades, making them popular in heirloom collections.
Here’s what you need to know to plant and enjoy peonies in your garden.
Most species of peonies (Paeonia sp.) fall into two types:
- Garden Peonies: Herbaceous perennials, which means that they die back in the fall, overwinter underground, and sprout anew in the spring. They grow in large, rounded clumps – often 2-3 feet in diameter – that are well suited for borders, backdrops, or as specimen plants.
- Tree Peonies: Deciduous shrubs that lose their leaves in the fall but keep the stems aboveground. They are frequently grafted onto sturdy root stock. Tree peonies can grow up to 8 feet tall and are usually used as specimen plants.
Peonies are classified according to the flower type (single or double), color (any except blue), and bloom time (early, mid, or late spring), which means that there’s a variety to suit every garden! From soft single blossoms that drape like silk, to ruffled double blossoms resembling massive pompoms, peonies are sure to add a stunning element to any landscape.
- Hardiness: Peonies grow in Zones 3-8, with some varieties stretching to zones 2 and 9. Tree peonies are generally less hardy, to zone 4.
- Light: Full sun, with some light shade tolerated during very hot summers.
- Soil: Rich, well-draining soil that is neutral to slightly acidic. Peonies easily rot if waterlogged, so drainage is critical.
- Water: Peonies may need irrigation during dry seasons. Water deeply, allowing soil to dry out between waterings.
- Space: Peonies are large plants that don’t compete well with trees and shrubs. For best results, give them plenty of space in an open ornamental planting bed.
- Time: Peonies often take several years to become established.
How to Plant Peonies
The best time to plant peonies is in the fall, so that they can develop tiny feeder roots before going dormant for the winter. Spring growth concentrates so heavily on leaves and blooms that spring-planted peonies will struggle to get roots established. Incorporate some well-rotted compost into the planting hole along with additional amendments for drainage if needed.
Planting Garden Peonies:
Garden peonies should be planted fairly shallow. Look at the roots and locate the growth buds, where the stems sprout from the roots. The highest growth bud should be no more than 2” deep, or your peony may not bloom.
Planting Tree Peonies
Tree peonies are typically grafted onto the rootstock of garden peonies, so the planting technique is different. Tree peonies should be planted with the graft bud (the lump where the rootstock attaches to the stem) about 5”- 6” deep. This allows the grafted portion to form roots of its own. This is a unique practice for tree peonies, as most other grafted plants require the graft bud to be aboveground.
Caring for Peonies
Peonies are low-maintenance plants that prefer to be left alone. Here are some tips for caring for your newly planted peonies:
- Peonies benefit from mulch, especially to moderate temperatures during their first winter. Never pile mulch around the crown of the plant – it will cause the plant to rot.
- Garden peonies can live for 10 years or more without disturbance, but if they begin blooming poorly you can divide and propagate them just as you would any clumping perennial.
- Garden peonies should be cut back to the ground in the fall, because the dead foliage can breed fungus and disease. Tree peonies should not be cut back, beyond a light pruning for shape.
- Peonies planted in good soil typically do not need a lot of extra fertilizer. But, if desired, you can feed them with a balanced organic fertilizer in the fall.
- Garden peonies can be heavy and droopy when blooming. Install hoops, or gently stake the stems, to hold them up.
- Ants are attracted to the unopened flower buds, but they don’t harm the plant and will leave once the blooms open.
- The most common diseases for peonies are fungal. To prevent, minimize overhead watering and make sure there is adequate air circulation. Treat with a fungicide if necessary.
- Peonies make splendid cut flowers, but wait until they are at least three years old before cutting, and never cut more than half the blooms on each plant.