Peonies: planting, pruning, and caring for

Description and Botany

The genus Paeonia, comprising 33 deciduous species, is predominantly found in temperate Eurasia, with the exception of two species native to North America. Peonies, once classified among the Ranunculaceae family—which includes anemones and buttercups—are now recognised as forming their own family, the Paeonaceae. Among them, Chinese peonies (Paeonia lactiflora) stand out for their significant contribution to the diversity of herbaceous cultivars, while the varieties suffruticosa, delavayi, and lutea have enriched the range of shrub peonies.

These plants are characterised by a woody stump with fleshy, robust roots, ensuring remarkable longevity, sometimes lasting centuries. Their deciduous foliage consists of dentate or lobed leaflets, providing particular elegance to the shrub species, and some, like Paeonia tenuifolia, boast finely dissected leaves. In spring, peonies announce their awakening with the emergence of large red buds, whether from the ground for herbaceous types or on the branches for shrubs, revealing initially mahogany foliage that unfurls into vibrant green.

In autumn, herbaceous peonies can offer a spectacle of purple, ochre, and bronze colours, especially after a sunny and moderately dry summer. However, it is advisable to accompany these garden queens with other flowers to maintain aesthetic interest until the leaves fall in September.

The solitary and prominent flower buds at the end of the stems herald a flowering period that perfumes the surrounding air for about fifteen days, and even up to a month for hybrids in the Itoh range. Each flower, at its full bloom, lasts only one to two days, offering a fleeting moment of pure beauty.

The medicinal peonies, scientifically known as Paeonia officinalis, are a European species distinguished by their simple, bright red flowers. Highly fragrant, these flowers have more than five rounded petals, reminiscent of the large flowers of wild roses with their short yellow stamens. In double-flowered varieties, these stamens are replaced by undulating filaments, creating a visually captivating display. Medicinal peonies conceal between two and five large ovaries, which, after fertilisation, give rise to stout, hairy follicles. It is important to note the toxicity of the seeds of these plants, which are large enough to attract attention.

The pollination of peonies, essential for their reproduction, greatly benefits from the activity of bees. However, many cultivars, particularly double or triple-flowered peonies, present an impressive bouquet of transformed stamens, either into frizzy filaments in varieties like Paeonia lactiflora ‘Bowl of Beauty’, or into additional petals in specimens such as Paeonia officinalis ‘Rubra Plena’ or Paeonia lactiflora ‘Felix Crousse’. These transformations offer a palette of varied colours, ranging from delicate gradients to distinctive purplish touches, while presenting flower sizes from 5 to 30 cm in diameter. Some, particularly among shrub peonies, can become so heavy that they lean or even flop onto the ground, reminiscent of the morphological diversity of Dahlias.

The floral blooming of peonies requires patience and time, often taking two to three years after planting to establish a solid root system. Once well-rooted, peonies can bloom for a century, offering up to 60 flowers per plant. Shrub varieties require an even longer period, about seven years, to fully reveal their splendour, which explains the increase in price with the age of the plants. When purchasing, it is advisable to pay attention to the size of the stump and the number of eyes or branches, as these are indicators of the age and maturity of the plant.

Cut peonies, in particular, make magnificent additions to bouquets, pairing perfectly with lilacs and campanulas, and should ideally be harvested in the morning at the coloured bud stage.

Beyond their beauty, medicinal peonies possess medicinal virtues, a legacy of their Greek name “Paeonia,” meaning “healing.” This name may also derive from Paeon, a physician from ancient Greece. Pliny the Elder already regarded the peony as the oldest cultivated flower, a testament to its historical and cultural significance.

Some peony flowers: Paeonia lactiflora ‘Black Beauty’, Paeonia itoh ‘Julia Rose’, Paeonia lactiflora ‘Bowl of Beauty’ and Paeonia delavayi lutea

The main varieties of Peony

Herbaceous Varieties with Simple Flowers

Herbaceous Varieties with Double Flowers

Shrub Varieties

Paeonia lobata Sunshine

Undoubtedly the best of the varieties derived from botanical species, this rare perennial in cultivation produces simple, globular, shimmering flowers of a rare and brilliant red, a light currant red tinged with orange, further enhanced by a large heart of golden stamens. Its luminous flowering provides a beautiful backdrop in a border or large rockery.

• Flowering time May, June
• Height at maturity 85 cm

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Paeonia officinalis Mollis

Its deciduous green foliage tinged with purple serves as a setting for beautiful simple calyx-shaped flowers, a true bright pink with no trace of blue, opening to a heart of strong yellow stamens. Sometimes repeat flowering in July. Plant it in full sun or partial shade, in calcareous, fertile, loose soil that remains cool.

• Flowering time July, August
• Height at maturity 45 cm

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Paeonia tenuifolia

Very beautiful fine foliage reminiscent of fennel, topped with lovely ephemeral cup-shaped flowers of scarlet red. Dense and particularly fine deciduous foliage, of bright dark green. Cultivate in full sun or partial shade in a warm situation, in moderately dry soil.

• Flowering time May
• Height at maturity 40 cm

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Paeonia lactiflora Bowl of Beauty

An excellent cut flower, this Japanese-type peony consists of two rows of petals in a carmine pink and a large heart that turns from yellow to cream white. The flowers measure up to 12 cm in diameter and are grouped on stems.

• Flowering time June, July
• Height at maturity 90 cm

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Paeonia lactiflora Do Tell

A particularly floriferous Japanese-form peony with upright stems speckled with red, topped with large solitary, elegant, and fragrant flowers measuring 7 to 10 cm. Pale pink corolla with a petaloid heart that fades to pale lilac at the end of flowering.

• Flowering time June
• Height at maturity 80 cm

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Paeonia lactiflora Inspecteur Lavergne

An old reliable peony with large pom-pom flowers, a dark carmine pink, quite pure, in the shape of anemones, supported by sturdy stems that hold up well in the garden as well as in a vase.

• Flowering time June, July
• Height at maturity 80 cm

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Paeonia Itoh Julia Rose

A hybrid between a shrub peony and an herbaceous peony, characterised by significant growth and the production of flowers similar to those of shrub varieties. Semi-double flowers of 16 cm, tinted with pink and apricot on a soft yellow background, supported by sturdy stems.

• Flowering time June, July
• Height at maturity 75 cm

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Paeonia suffruticosa Pink - Tree Peony

Shrub peony with solitary, double flowers, 15 to 18 cm in diameter, tinted from soft pink to bright pink, adorned with yellow stamens. For a warm situation, protected from cold winds, in partial shade or non-burning sun, in well-drained, rich, humus-bearing, cool soil.

• Flowering time May, June
• Height at maturity 1,50 m

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Paeonia suffruticosa Lilac - Tree Peony

Shrub peony with solitary, semi-double, open cup-shaped flowers measuring 18 to 25 cm, lilac pink speckled with black and pale yellow stamens. Flowering from mid-May to mid-June.

• Flowering time June, July
• Height at maturity 1,50 m

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Paeonia suffruticosa Lu Mu Ying Yu - Tree Peony

Hybrid variety forming a bush at least 1.50 m in all directions, with exquisite and fragrant flowers reaching 20 cm in diameter, well double, whose crisped petals change from tender green to cream white. Sculptural in a border or as a solitary, this rare variety also offers excellent cut flowers. Suitable for any rich and cool soil. Sensitive to late frosts.

• Flowering time May, June
• Height at maturity 1,50 m

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Paeonia suffruticosa Wu Jin Yao Hui - Tree Peony

A magnificent, floriferous, and sturdy shrub peony, accessible to beginner gardeners. The bush, with a spreading habit, produces numerous rose-shaped flowers, slightly fragrant, measuring 16 cm wide, composed of multiple petals of a very dark red with a lustrous sheen. Provide it with bright exposure and good garden soil that is properly drained.

• Flowering time May
• Height at maturity 1,50 m

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Planting Peonies

Where to Plant Peonies?

Peonies do not like to be moved, so it is important to choose the best possible location to showcase them and ensure they do not suffer from excess moisture or competition from other plants. Remember, you are planting for the next two generations to come!

• Herbaceous peonies require full sun or partial shade with heavy (clay) soil that is rich, well-drained, yet remains cool in summer, neutral, slightly acidic, or calcareous (ideal pH between 6 and 7). Growth is slow, but flowering is more beautiful than in dry soil. Very sandy, well-draining soil produces a lot of foliage with few flowers. You can lighten overly wet soils in winter by adding some compost or leaf mould or by planting on a mound.

Itoh peonies appreciate partially shaded locations such as the edge of a grove or the shelter of a hedge and also require rich, cool, deep, and well-drained soil.

• Place shrub peonies in a warm location, facing west, sheltered from severe frosts and cold winds. Choose a sunny spot that is not scorching to slightly shaded (4 to 6 hours of sun/day). Flower buds and young leaves are sensitive to late frosts.

Shrub peonies prefer a rich, humus-bearing, deep, cool, and well-drained soil and tolerate calcareous conditions well. They are averse to very heavy, wet soils in winter. Slow to grow in the first few years, shrub peonies develop a powerful and deep root system and produce few branches; it is only after 3-4, sometimes 5 years of cultivation that branching thickens and flowering becomes spectacular. Mature plants do not like to be moved.

To learn more, read Planting Peonies: Where, When, and How and How to Have Beautiful Peonies in the Garden?

When to Plant?

Plant herbaceous peonies preferably in autumn to allow them time to settle in.
For shrub peonies, spring planting is preferable, especially if winters are harsh.

How to Plant?

This plant can be quite temperamental and may take a long time to flower.

• Dig a hole 40 to 50 cm deep.

To check if your soil drains sufficiently, dig a hole 30 cm deep and 20 cm wide and fill it with water. After an hour, the water should be completely drained.

• Lay a 10 cm thick layer of gravel and lighten the soil with coarse sand if necessary.
• Add decomposed manure or dried blood to the planting hole to stimulate flowering.

For herbaceous peonies, position the crown of roots (claw) no more than 3 cm deep and spaced 60 cm to 1 m apart.

Roots of herbaceous peony (photo F. D. Richards – Flickr)

For shrub peonies, do not hesitate to bury the grafting point 10 cm deep so that the graft produces its own roots. Indeed, the grafting system on herbaceous peony reduces the longevity of the shrub peony. On the other hand, planting too shallowly causes the rootstock to sprout. However, maintain the same level as the substrate if your plant is sold in a container.

• Replace the soil and lightly compact it.
• Insert supports such as hazel branches to support the large flowers and mark the location.
• Water generously.
• Avoid mulching with organic waste to prevent disease transmission. Instead, install low-competition groundcover plants such as hardy geranium or sedum.

Entretien

• Apply decomposed manure or dried blood each autumn 15 cm from the base. Avoid fresh manures!
• If an exceptional frost affects the branches of the shrub peony, and if you have taken care to bury the grafting point, cutting the branches back to the ground in April allows for the reconstitution of the branches within a year.
• In the first few years, water the peony during dry spells, especially in spring, before flowering.
• Cut faded flowers to prevent the plant from exhausting itself with seed production.

• In general, herbaceous peonies do not require clump division, unless their flowering decreases. Shrub peonies should not be pruned or only minimally (thin and crossing branches); to learn more, read our article “How to prune shrub peonies?”
• Peonies are very little susceptible to diseases except in cases of excessive soil moisture (white rot) or air humidity (grey rot, rust), particularly in herbaceous peonies. Cut back diseased parts to healthy tissue, spray with 2% Bordeaux mixture or horsetail decoction as a preventive measure, and do not leave any plant debris at the base. Golden beetles sometimes eat the flowers without serious consequences. Also read our topic: diseases and pests of shrub peonies.

→ A shrub peony that flowers little or not at all? Read our tips in: My shrub peony is not flowering. Why?

Clump of herbaceous peony in early spring

Multiplication: dividing peonies

Tree peonies are generally grafted onto herbaceous peony roots as propagation by cuttings is not easy. This is a specialist task. This method involves a cultivation period of 2 to 3 years in a nursery, which explains their high cost.

Clump division is possible with herbaceous peonies and must be done if you move the plant, or you risk not seeing it bloom again. Proceed in autumn or early spring.

Clump Division

• Remove the entire clump without damaging the roots using a forked spade.
• Divide the clump with a sharp knife, ensuring to keep 3 to 5 roots and 3 to 5 buds per division.
• Replant with the buds placed no more than 3 cm from the surface.

→ Learn more in our tutorials: How to divide an herbaceous peony? and How to propagate the tree peony?

Uses and Associations

Peonies were once among those plants that formed the backbone of a garden. Every garden, from the most modest to the most elaborate, proudly displayed clumps of fragrant flowers in spring, making their way into the home, accompanying lilacs and blue campanulas in every bouquet. Japanese peonies integrate perfectly into a mixed border alongside timeless perennials such as columbines, delphiniums, campanulas, irises, alyssums, carnations, foxgloves, lupins, or even Christmas roses, or ferns when the area is partially shaded. Just ensure they have enough space so they are not competing with one another. Only long-term pot cultivation is not recommended, as their needs will not be met. Over time, the peony becomes majestic, multiplying and flowering more abundantly. They can also be planted at the base of a standard rose. When planted in isolation, place 3 plants spaced 60 to 100 cm apart for a spectacular effect.

An example of association: Paeonia lactiflora ‘Félix Crousse’, Geranium pratense ‘Mrs Kendall Clarke’, Rose ‘Astronomia’, Geranium ‘Johnson’s Blue’, and Rose ‘Munstead Wood’

The Itoh peony thrives in partially shaded locations such as the edge of a grove or the shelter of a hedge. It is often planted in groups of 3 in a shrub or perennial bed.

Botanical peonies (officinalis, tenuifolia, etc.) that enjoy warm situations can be placed at the top of a large rockery, even limestone, or in a bed or isolated.

Plant the shrub peony in isolation or framed by other plants depending on the exposure, alongside ferns, rhododendrons, and hydrangeas in partial shade, or with irises, nepeta, foxgloves, and daisies in a sunny area. Consider pairing with plants that will take over the flowering in summer, such as Phlox paniculata, dahlias, or asters.

Gwenaëlle offers you more beautiful association ideas in: Associating shrub peonies in a bed.

An example of association in light shade and cool soil: Paeonia delavayi lutea (or a double-flowered variety like ‘Alice Harding’), Dryopteris affinis, and Iris sibirica ‘Butter and Sugar’ (or a similar variety like ‘Snow Queen’)

→ Discover more association ideas with peonies in our advice sheet!

Did you know?

Herbaceous peony (Paeonia lactiflora), cultivated for over 1000 years in the East, was only known in Europe by the late 18^th century thanks to a gift given to Josephine by the Emperor of China. The shrub peony, also Asian, was discovered by the West only a century later. There are also peonies native to the West, such as the officinalis, described by the Greeks as possessing great medicinal virtues.