Delavay’s tree peony

Delavay’s tree peony: how do you recognise it?

Habit

Upright, woody shrub about 1.5 m tall and wide, which forms a broader clump over the years.

Foliage

Deeply cut into narrow lobes; dark green above, blue-green beneath.

Flowers

Nodding, cup-shaped flowers, deep red, with golden stamens, in May–June.

Fruit

Curved pods that split open in autumn to show black seeds.

Roots

Thick and fleshy; it dislikes being moved, so choose the right spot straight away.

Flowering: May–June · Plants: September–October

Why grow it?

• Nodding, deep red flowers with golden stamens in May–June: an unusual colour for a shrub.
• Beautiful, deeply cut foliage that stays attractive all summer.
• Very hardy and low-maintenance, with no pruning.
• A woody shrub with a natural, airy shape, and the stems are visible in winter too.
• Bees visit the flowers, which are rich in nectar and pollen.
• A long-lived plant that grows quietly for years and improves with time.

Delavay’s tree peony: where does it grow best?

• Sun or part shade; a spot with light shade in the afternoon is ideal.
• Well-drained, humus-rich soil: sand, loam or clay, acid to chalky.
• Normally moist, without wet feet.
• Sheltered from strong wind and from late spring frosts, which can damage young shoots.
• Allow 1.5 m of space per shrub.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

1.5 m tall, 1.5 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Cranesbill: Pink and purple flowers that go well with the deep red.
• Hosta: Broad foliage at the foot, in the same spot.
• Lady’s mantle: A light, yellow-green edge at the front of the border.
• Ornamental grasses: Soft, swaying stems next to the heavy flowers.

Delavay’s tree peony: when and how to plant it?

Plant in September–October.

1. Plant in September–October, while the soil is still warm and not too wet.
2. Dig a generous hole, at least 50 cm wide, and mix in compost and a little sand if the soil is heavy.
3. Set the plant at the same depth as in its pot. A grafted plant goes in with the graft union about 10 cm below ground, so that the scion makes its own roots.
4. Leave 1.5 m between shrubs and let it grow freely.
5. Water thoroughly straight away.
6. Spread a layer of leaf mould or bark around the base, without covering the stems.

Care

Water

In the first two summers, water generously every week in dry weather. After that it is rarely needed.

Feeding

Compost or organic fertiliser in March–April. Do not give too much nitrogen.

Mulching

A layer of leaf mould in spring keeps the roots cool and the soil moist.

Seed pods

Leave the pods on for their ornamental value; in autumn they split open to show the seeds.

Moving

It dislikes being moved: choose the right spot straight away and leave it in peace.

Tip: Plant it in September–October in a sheltered spot and leave it unpruned: cutting costs flowers. Water it in dry weather during the first two summers.

Delavay’s tree peony: when to prune it?

When: It does not need pruning. In April–May, when the buds break, remove only dead or frosted branches.

How:

• Cut dead branches back to healthy wood.
• Cut frosted tips back to just above a healthy bud.
• To keep a shrub open and airy for years, now and then remove a dead stem right at the base.

Caution: Do not cut into healthy wood: the flower buds sit at the ends of last year’s branches, so every branch you cut off costs you flowers.

Pruning calendar and basic rules

Propagation

Seed

Sow fresh seed in September–October in a pot or outdoors. It germinates slowly: the root often grows in the first year and the shoot only appears after the next winter.

Suckers

If the shrub produces suckers, in September–October you can detach a rooted sucker and plant it elsewhere.

Delavay’s tree peony: how does it get through the winter?

Hardy to −20 °C.

• Very hardy, down to about −20 °C: no protection is needed in Flanders.
• Young shoots in spring can be frosted by late night frosts; cover them with horticultural fleece.
• In a pot, stand it against a wall and wrap the pot in hessian so the roots do not freeze.

Diseases and pests

• Late frost: Young shoots and buds turn black after a cold night in spring. Cover with fleece and cut out damaged parts later.
• Grey mould: Buds and shoots wilt and become covered in grey mould in a wet spring. Cut out affected parts and dispose of them with household waste.
• Poor flowering: Young plants only flower after a few years; too much shade or soil that is too wet holds back flowering.
• Slugs: They nibble young shoots in spring. Collect them by hand or set up a barrier.

Through the year

• March: Apply compost or organic fertiliser. Check stems for frost damage.
• April: Cut out dead or frosted branches. Keep slugs off.
• May: Flowering begins.
• June: Flowering. Then leave the pods on.
• July: Water in dry weather, especially young shrubs.
• September: Plant. Sow fresh seed.
• October: Plant. Mulch.
• November: Mulch. Nothing more to do: rest.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Tree peonies are true woody shrubs: their stems stay in place over winter, unlike the herbaceous garden peony, which dies back to the ground.
• In the wild it grows in the mountains of Yunnan and Sichuan at altitudes above 2,000 m.
• It is named after Jean-Marie Delavay, a French missionary and plant collector of the nineteenth century.