How to Grow and Care for Chinese Peony (Common Garden Peony)

Few plants have a longer history of cultivation or a more important role in ornamental gardening than peonies. Of the many species within the Paeonia genus, arguably the most popular and important is the Chinese peony (P. lactiflora), also known as common garden peony. These clump-forming, shrub-like perennial plants have enormous, highly fragrant flowers that appear in late spring and early summer.

Well-developed potted peonies from the nursery are planted in the spring, but bare-root plants, often ordered from online retailers, are typically planted in the fall. Chinese peony is a slow-growing plant that can take as long as three years to become mature enough to bloom, but you’ll be rewarded for your patience with a long-lived plant—they may survive 100 years or more.

Peonies contain a toxic substance, paeonol, that can cause gastrointestinal distress if ingested by pets. Peony is not included on lists of plants toxic to humans.

Chinese Peony Care

Peonies require winters cold enough to induce plant dormancy, so they are rarely used as garden plants in areas higher than USDA zone 7. On the other hand, many varieties are hardy down to minus 50 degrees Fahrenheit, so they are greatly prized in most northern gardens.

When planting peonies, generous spacing and good air circulation are crucial because overcrowding encourages the spread of diseases—three to four feet between plants is recommended. Keep them well away from other large plants that might compete for nutrients. Because Chinese peony requires a winter chill to set flower buds, they should be planted so the root crown is quite close to the surface—no more than two inches deep. If planting a nursery-grown specimen, make sure not to bury the crown deeper than it was growing in the pot.

The flower heads of peonies are large and heavy so they tend to flop over, especially after it rains. If you do not want to buy special peony rings you can use wooden or light metal stakes and twine to make your support.

The only other regular maintenance peonies require is the removal of the foliage and thorough fall cleanup. During the growing season, for a neater appearance and to prevent the spread of disease, remove any diseased leaves.

Light

For the best bloom, garden peonies need full sun with at least six hours of daily sunlight. The only exception is in warmer climates where you can plant them in partial shade to protect them from the midday heat.

Soil

Peonies can grow in many different soils as long as the soil is fertile and well-drained. Avoid wet locations where water pools. If the soil is sandy or high in clay, add organic matter but not manure, as this can encourage botrytis disease. When adding amendments to the soil, make sure to mix them in deeply. Peonies prefer a relatively neural soil pH but will tolerate mild acidity.

Water

Generally speaking, Chinese peonies do not require extra watering in regions with regular rainfall. Their water needs are the highest in the spring and fall so if there are dry conditions during those crucial months, keep the soil evenly moist by watering them slowly and deeply as needed. About one inch of water weekly, through a combination of rainfall and irrigation, is the standard.

Temperature and Humidity

Peonies are perennials for cool climates—many varieties will survive temperatures as low as minus 50 degrees Fahrenheit. They need winter chill to induce the full dormancy that resets the growth buds. Chinese peonies thrive in zones 3 to 7, however, the northern part of zone 8 can also support peonies.

Chinese peonies don’t do well in strong heat and humidity, especially during the bloom period. In regions with warm, humid summers, one workaround is to select varieties that bloom earlier, before the onset of the summer heat.

Fertilizer

Chinese peonies generally don’t need fertilizer unless the soil is lacking in nutrients. In poor soil—or if the plants are not flowering adequately—apply a low-nitrogen fertilizer, such as bulb fertilizer, after the bloom period and again in the late summer, around the dripline of the plants.

But it's best not to feed peonies at all until there's evidence of need—such as plants that don't flower even though all other conditions are favorable.

Types of Chinese Peonies

Chinese peonies have been cultivated for centuries and there are many hundreds of cultivars, as well as P. lactflora x hybrids. Of the many hundreds of named cultivars of Chinese peony, these are some of the most popular:

• Paeonia lactiflora ‘Sarah Bernardt’ is a fragrant late-season bloomer with rose-pink double flowers.
• P. lactiflora ‘Karl Rosenfield’ is a crimson-colored mid-season bloomer with double flowers.
• P. lactiflora ‘Shirley Temple’ is a fragrant, early bloomer with double, light-rose flowers that gradually fade to ivory.
• P. lactiflora ‘Bowl of Beauty’ is a fragrant, early-season bloomer with single pink flowers and frilly off-white to yellow centers.
• P. lactiflora ‘Kansas’ is a fragrant, early to mid-season bloomer with bright pink-red double flowers.
• P. lactiflora ‘Festiva Maxima’ is a highly fragrant, early-season bloomer with double white flowers.

Among the many cultivars of Chinese peony, there are sixpeony flower types to choose from ranked from simple single-petal flowers to extremely full and heavy double-flowered types. Anemone, single, and Japanese types have relatively open, lightweight blossoms, while semi-double, double, and bomb types have much fuller, heavier blossoms that are sometimes susceptible to collapsing stems, especially after a rainfall.

Other Types of Peonies

In addition to the Chinese peonies and hundred cultivars of P. lactiflora, several other major peony categories are common garden plants:

Tree peonies include a select group of Paeonia species, especially Paeonia suffruticosa, that are woody shrubs with flowers that are very large but more open than those of Chinese peonies. Because the plant stems are very sturdy, the flowers are less susceptible to flopping. Tree peonies are hardy in zones 4 to 8. These are quite expensive plants, however.

Itoh peonies, also known as intersectional peonies, include many cultivars of a particular hybrid peony that was bred by crossing a tree peony species (P. lemoinei) with Chinese peony (P. lactiflora). They have the large showy flowers of tree peonies on plants that more closely resemble Chinese peonies.

Fern-leafed peonies, include Paeonia tenuifolia and a few cultivars. These delicate plants have dark red flowers and beautiful fern-like foliage quite unlike the other peony types.

Pruning

Spent flowers should be deadheaded to prevent fungal diseases and to keep the plants attractive. Cut off the flower stalks down to just above a strong leaf.

In the fall, cut the entire plant back to just above ground level. Remove and destroy the debris to eliminate fungal spores that might reinfect the plant in spring.

Propagating Chinese Peony

Peonies are best propagated by digging up and dividing the rhizomatous root clumps, but this is a somewhat tricky operation. Here's how to do it:

1. In fall, use pruners to cut back the plant's stalks to a few inches above ground level, then carefully dig up the entire plant.
2. Use a sharp knife to divide the root ball into sections, each having three to five growth eyes at the top of the section.
3. Replant the pieces in the desired locations, making sure the growth eyes are buried no more than two inches deep. Planting too deep will prevent the roots from getting the winter chill they need and may compromise flowering.

Be patient, because a root division may take three years or even more to develop into a mature flowering plant.

How to Grow Chinese Peony From Seed

Nearly all peonies are hybrid plants that don't "come true" from seeds collected from the flower heads. Even if you buy seeds from a reputable commercial source, it can take many years for seedlings to grow into mature flowering plants. For this reason, seed propagation is rarely done by amateurs, who find it much easier to propagate by vegetative means.

Potting and Repotting Chinese Peony

Because they are so tall and top-heavy, Chinese peonies tend to topple over when planted in containers. If you want to grow them this way, choose dwarf hybrids, also called patio peonies.

Overwintering

It's a bad idea to give Chinese peonies too much winter protection, as they count on a severe winter chill to reset the flowering buds. Gardners who heap mulch over the plants in winter with good intentions may be surprised by plants that refuse to flower the next year.

But it is a good idea to cut the plants down to just above ground level and clean away all debris around the peonies before the snow sets in, as this prevents fungal spores from overwintering and reinfecting plants the following spring.

Common Pests & Plant Diseases

The most common diseases affecting Chinese peonies are botrytis blight and other fungal diseases, which can be especially troublesome in wet, cool spring weather. If you notice diseased, blackened, or wilted leaves or stems, remove them promptly to prevent the spread of the disease. In the fall, cut the herbaceous stems down to a few inches and dispose of them in the garbage. If you find that your peonies are susceptible to fungal disease, a weekly spray with a fungicide early in the season may prevent diseases from becoming serious.

Mildew, which is also a fungus, appears as a white coating on leaves and stems, mostly in hot, humid summer weather. It is merely unsightly and does not harm the plants. Here, too, a thorough fall cleanup helps prevent the plants from getting reinfected in the following year.

Peonies are largely free of serious pest problems, though they can be susceptible to thrips, scale, mealybugs, bulb mites, and beetles, all of which can be treated with neem oil or pyrethrin-based organic insecticides. The ants that often cover peony blossoms are utterly harmless, drawn to the nectar in the flowers.

How to Get Chinese Peony to Bloom

Given good sun exposure, mature peonies usually are quite willing to bloom vigorously. Young plants, however, may take three years or so before they bloom, so don't be discouraged if a bare-root planting or divided peony doesn't flower in its first few years.

A peony that is planted too deep may refuse to bloom because its growth eyes have not received the proper winter chill. Try digging up the plant and planting it a little shallower. Finally, if the soil is poor, a fall dose of bulb fertilizer may jolt the plant into better blooms the following spring. Be careful not to overfeed, though, as excess fertilizer can also hinder blooms.

A plant that is harvested too heavily for cut flowers may also respond with reduced blooms the following year. To ensure a good annual display, never harvest more than one-third of the flowers for cut arrangements.

Common Problems With Chinese Peony

There are only a couple of common complaints with this largely trouble-free plant.

Flower Stems Flop Over

Peonies suffer from the horticultural industry's success at breeding plants with huge double-petaled flowers. The enormous blossoms found on many varieties often collapse under their sheer weight, especially after a rainfall soaks the petals. The answer: Use gridded plant supports that offer reinforcement to the flower stems that grow up through the grid openings. Or, plant varieties with single or anemone-type flower petals.

Plant Turns Mushy and Collapses

This is the classic sign of botrytis disease or other serious fungal diseases. By the time such symptoms arise, it's probably too late to save the plant; you'll need to dig it up and destroy it. If you find that peonies are susceptible to these diseases in your garden, then early spraying with fungicides may help prevent disaster.

Flowers Are Covered With Ants

Don't worry. This is entirely normal, as ants are drawn to the sweet nectar and scent of the flowers. They do not injure the blossoms, and ants can be easily brushed away before you bring cut flowers indoors for flower arrangements.

From: thespruce