Chinese astilbe

Chinese astilbe: how do you recognise it?

Habit

Compact clump about 50 cm tall and 40 cm wide; the low forms stay under 30 cm and spread by short runners.

Leaves

Compound and finely divided, with toothed leaflets; dark green and matt.

Flower

Dense, upright plumes of countless tiny flowers, from July to September.

Colour

Usually lilac-pink; there are also cultivars in pink, purple-red and white.

Seed heads

Rusty brown after flowering; they stay decorative until spring.

Roots

A shallow rootstock with fine roots: the soil must not dry out.

Flowering: July–September · Plants: March–April and September–October · Pruning: March

Why grow it?

• Flowers from July to September, when many other shade plants have finished.
• Tolerates more sun and drought than other astilbes.
• The low forms make a dense ground cover that gives weeds little chance.
• The rusty-brown seed heads stand all winter and look lovely covered in frost.
• The finely divided foliage is decorative too, from spring to autumn.

Chinese astilbe: where does it grow best?

• Partial shade is ideal; full sun only if the soil stays moist.
• Humus-rich, moisture-retentive soil: loam, clay or peat, acid to neutral. It dislikes chalky soil.
• Moist to wet: it is happy beside a pond or stream, but not in standing water.
• Plant 30–40 cm apart; the low ‘Pumila’ 25–30 cm apart for a dense ground cover.

Light

Sun and partial shade

Soil type

Loam, clay or peat

Acidity

Acid or neutral

Moisture

Normal or wet

Size

0.5 m tall, 0.4 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Hosta: Large, calm leaves beside the airy plumes, in the same moist partial shade.
• Ferns: Delicate green that complements the divided astilbe leaves.
• Coral bells: Coloured leaves for a low foreground.
• Japanese forest grass: Arching golden or green blades along the edge of the border.
• Purple loosestrife: Flowers at the same time, in the same moist soil, with straight pink spikes.

Chinese astilbe: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Loosen the soil and mix in plenty of compost or leaf mould: it holds moisture.
3. Set the plant at the same depth as in the pot, with the buds just at soil level.
4. Leave 30–40 cm between plants, or 25–30 cm for ground cover.
5. Water well straight away and keep the soil moist for the first few weeks.
6. Spread a mulch of leaf mould around the plants.

Care

Water

Never let the soil dry out, especially in sun. In dry spells give a full watering can at the base every week.

Feeding

Compost or organic fertiliser in spring: it likes a rich soil.

Mulching

A layer of leaf mould or well-rotted manure in spring keeps the soil cool and moist.

Spent plumes

Leave them: they stay attractive into winter. Cutting them off does not bring new flowers.

Dividing

Every 3–4 years, when the centre of the clump goes bare or it flowers less.

Tip: Keep the soil moist with a thick layer of leaf mould; it will then tolerate even a sunny spot. The low ‘Pumila’ forms a dense carpet within a few years.

Chinese astilbe: when to prune it?

Pruning months: March.

When: Once a year, in March, before the new leaves appear.

How:

• Cut the old stems and dead leaves back to just above the ground.
• Take care not to damage the new pink buds already at the base.
• There is no need to remove spent plumes in summer: no second flush will follow.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September: lift the clump and cut it with a sharp knife or spade into pieces, each with a few buds and roots. Replant straight away and water.

Runners

With ‘Pumila’, slice rooted pieces off the edge in spring and replant them elsewhere.

Chinese astilbe: how does it get through the winter?

Hardy to −35 °C.

• Fully hardy, to about −35 °C: no protection is needed in Belgium.
• Leave the brown plumes standing: they look lovely with frost and protect the crown.
• In a pot: the root ball must not dry out in winter, nor sit in water; stand the pot sheltered against a wall.

Diseases and pests

• Scorched leaves: Brown, crisp leaf edges in summer mean too dry or too much sun. More water, a mulch and perhaps a shadier spot.
• Vine weevil: Notched, half-moon bites along the leaf edges and a plant that suddenly wilts: the larvae eat the roots, especially in pots. Control with nematodes in spring or late summer.
• Slugs: They eat young shoots in spring. Pick them off in the evening or set a beer trap.
• Poor flowering: An old, congested clump or soil that is too dry. Divide it and improve the soil with compost.

Through the year

• March: Cut back old stems. Add compost. Plant and divide.
• April: Plant. Mulch. Watch for slugs.
• May: New leaves. Water in dry spells.
• June: Flower buds appear. Keep the soil moist.
• July: Flowering begins. Water in dry spells.
• August: Full bloom. Water generously in hot weather.
• September: Last flowers. Plant and divide.
• October: Plant. Leave the plumes standing.
• December: Rest. The brown plumes decorate the winter border.

Did you know?

• Astilbes are sometimes called false spiraea because their plumes resemble those of spiraea, but they are not related: astilbe belongs to the saxifrage family, spiraea to the rose family.
• The name Astilbe comes from Greek and means ‘without sparkle’, probably referring to the matt leaves.
• Chinese astilbe is one of the latest astilbes to flower: it starts when most others have finished.