Tree peony

Tree peony: how do you recognise it?

Habit

Woody, sparsely branched shrub 1.5 m tall and wide. It grows slowly and stays open.

Leaves

Large, doubly divided and deeply cut, fresh green to blue-green. They fall in autumn; the woody stems remain.

Flowers

Cup-shaped flowers 15–25 cm across in May, with silky petals around a centre of yellow stamens. Single, semi-double or double.

Scent

Light and sweet in many varieties; it varies a lot between varieties.

Roots

Deep and fleshy. Once planted it dislikes being moved.

Flowering: May · Plants: September–October · Pruning: April and June

Why grow it?

• Huge, silky flowers in May: one of the most spectacular plants in the garden.
• Often fragrant and beautiful as a cut flower.
• Attractive outside the flowering season too, with large, deeply cut, often blue-green leaves.
• Single and semi-double flowers with their yellow centres are popular with bees and bumblebees.
• A plant for life: it can stay in the same spot for decades and gets better every year.

Tree peony: where does it grow best?

• Sun or light partial shade; in partial shade the flowers last longer.
• Sheltered from strong wind and preferably not facing east: early morning sun after a frosty night damages young shoots.
• Deeply dug, rich, well-drained soil: sand, loam or clay, acid to chalky. It will not tolerate standing water.
• Moist; in spring the soil must not dry out.
• Allow 1.5 m and do not plant it right next to trees or large shrubs whose roots compete with it.

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

• Hardy geranium: Flowers at about the same time and covers the base without smothering it.
• Lady’s mantle: A fresh green, low edging that sets off the big flowers.
• Catmint: Blue clouds at its feet that flower for a long time.
• Ornamental onion: Purple globes that rise above the border in May–June.

Tree peony: when and how to plant it?

Plant in September–October.

1. Plant in September–October, so it can still make roots before winter.
2. Choose its permanent spot straight away: it dislikes being moved.
3. Dig a hole 50–60 cm deep and wide, loosen the bottom and mix in plenty of compost.
4. Plant deep enough for the graft union to be 10–15 cm below the surface: the tree peony will then form its own roots.
5. Backfill, firm in and water thoroughly straight away.
6. Spread a layer of compost or leaf mould around the plant, but not against the stem.

Care

Watering

Weekly in dry weather for the first two years, especially in spring when the buds are forming.

Feeding

Compost around the plant in March, not against the stem. On poor soil, a handful of organic fertiliser.

Support

Heavy flowers droop after a shower. A sturdy stake or plant support keeps them upright.

Deadheading

Cut faded flowers back to a good leaf in June, unless you want the seed pods to ripen.

Late frost

Keep fleece handy in April and cover the shrub when a night frost is forecast.

Cut flowers

Cut in the morning, when the bud is just starting to open, and keep the stems short to spare the shrub.

Tip: Plant it in autumn with the graft union 10–15 cm below the surface and never move it again: with patience you will get more flowers every year.

Tree peony: when to prune it?

Pruning months: April and June.

When: Only remove dead wood, in April, when you can see which buds are breaking. Cut off faded flowers in June.

How:

• In April, cut dead twigs and frosted tips back to just above a healthy, swelling bud.
• In June, cut faded flowers back to above the first good leaf.
• Renovate an old, bare shrub carefully: cut no more than one old stem a year back low down, just above a bud.
• Shoots with different leaves coming up from the ground are from the rootstock: remove them right back to the root.

Caution: Never prune it hard: the flower buds are on the old wood, and it recovers slowly.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

In spring, bend a low branch down to the ground, lightly nick the bark and cover with soil. Sever it after one or two years. It does not always work.

Seed

Sow fresh seed in autumn in a pot outdoors. It germinates slowly and seedlings only flower after many years, often in a different colour.

Grafting

Nurseries graft it onto the root of a herbaceous peony. That is tricky at home: buy a grafted plant instead.

Tree peony: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: the shrub itself needs no protection in Belgium.
• It comes into growth early, so late frosts in March–April can damage young shoots and buds. Cover it with fleece on frosty nights.
• Keep mulch away from the stem so the wood does not rot.
• In a pot: choose a large, deep pot and stand it in a sheltered spot against a wall in winter.

Diseases and pests

• Grey mould: Buds and young shoots turn brown and rot, sometimes with grey fuzz. Cut out affected parts, put them in the household waste, water at the base and choose an airy spot.
• Late frost: Young shoots droop and turn black after a cold night. Cut them back to healthy wood; covering prevents it.
• Rootstock suckers: Shoots with different, less divided leaves come up from the ground: that is the rootstock. Remove them right back to the root.
• Few or no flowers: A young plant often needs two or three years. Too much shade, too much nitrogen or hard pruning also cost flowers.

Through the year

• March: Compost around the plant. The buds are breaking: get fleece ready.
• April: Remove dead wood. Cover on frosty nights. Put in a support.
• May: In flower. Cut flowers for the vase.
• June: Deadhead. Water in dry weather.
• July: Water in dry weather. Watch for rootstock suckers.
• September: Planting. Sow fresh seed.
• October: Planting. Clear fallen leaves to prevent grey mould.
• November: Mulch around the plant, not against the stem.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• In China it is called the king of flowers. The city of Luoyang is famous for it and holds a peony festival every spring.
• The name Paeonia refers to Paeon, the physician of the gods in Greek mythology.
• Nurseries graft tree peonies onto the root of a herbaceous peony. Planted deep, it forms its own roots after a few years.