Tree peonies (Paeonia suffruticosa) are deciduous sub-shrubs that bloom in mid to late spring with big, beautiful peony flowers. The flowers are much like those of their cousins, the familiar herbaceous perennials, Paeonia lactiflora. Tree peonies also have attractive leaves, so if you love peony flowers and want a woody plant that has aboveground structure throughout the year, tree peonies might be the perfect choice.
Tree peony shrubs work well as hedge plants or as borders along a driveway, path, or property line. They typically reach only about 4 or 5 feet tall, making them more of a symbolic barrier or border than a privacy screen. Once their spectacular blooms have died, the green-leaved shrubs provide an attractive backdrop for other plants. They grow best in climates with hot summers and cold winters, making them great plants for much of the eastern, midwestern, and western United States.
|Botanical Name||Paeonia suffruticosa|
|Common Name||Tree peony|
|Plant Type||Deciduous shrub|
|Mature Size||3 to 5 feet tall and 3 to 4 feet wide|
|Sun Exposure||Full sun to part shade|
|Soil Type||Fertile loam|
|Soil pH||6.8 to 7.5|
|Flower Color||White, red, pink, purple, yellow|
|Hardiness Zones||4 to 8|
|Native Area||China, Bhutan|
How to Grow Tree Peony
Tree peonies sold nurseries and garden centers are typically the result of grafting. The scion is a tree-peony cutting that has been grafted onto an herbaceous rootstock. Be sure to plant the graft union at least 2 inches below the soil surface. Some nurseries recommend more; follow the instructions on the label, if any, that come with the plant. Often, there is a plastic ribbon indicating the recommended planting depth. Proper depth will promote the establishment of the scion's root system.
Like the herbaceous peony flowers, tree peonies do not like to be transplanted. So find a suitable home in which to establish them when planting, and consider it their permanent home. Tree peonies are very slow-growers and may take three years before new plants fully establish and begin to flower. Once established, they are long-lived and need little maintenance.
Grow tree peonies in full sun to dappled shade. The flowers may suffer in hot summer sun; providing some shade helps.
Tree peonies have medium water needs and should not be overwatered. It's not a good idea to plant them where they will be watered by lawn sprinklers. Water deeply after the top 4 inches of soil have dried out.
Temperature and Humidity
Tree peonies have chilling requirements, so they grow best in regions that experience cold temperatures during the winter. The further south you go in their range, the more sense it may make to grow them in dappled shade. For fall care, mulch to provide additional winter protection if you live in an area where the plants are only borderline-hardy.
Adding a layer of compost or manure to the soil in spring will give the shrub a boost of nutrition to start the season. Many gardeners also like to feed their tree peonies with a foliar spray of fish emulsion later in the season.
Varieties of Tree Peony
- P. suffruticosa 'Red': Bears a gorgeous pink flower (not red); blooms relatively early in spring
- P. suffruticosa 'Kinkaku': Bicolored flowers of pale yellow with pink edges; blooms a few weeks later than P. suffruticosa 'Red'
- P. suffruticosa 'Kinshi': Also called the "Golden Bird," because it bears huge flowers in a golden-yellow color
- P. suffruticosa 'Qing Xiang Bai': Produces single blooms (most tree peonies have double blooms)
Pruning is rarely necessary on tree peonies. They are not like herbaceous peonies, which are cut or die back to the ground each year. However, you should prune the shrub to remove dead branches. If there are branches that result from suckering from the herbaceous rootstock, remove those too. When you do prune, wait till early spring to perform the operation; avoid pruning in fall, as aboveground growth helps shelter the root system in winter.