Bushy aster

Bushy aster: how do you recognise it?

Habit

Compact, rounded clump 30–50 cm tall and 40–50 cm wide, with many thin, densely branched stems.

Leaves

Narrow and lance-shaped, 2–6 cm long, dark green, arranged alternately along the stems.

Flower

Daisy-like flowers 2–3 cm across with a yellow centre, produced in large numbers from August to October.

Colour

Depending on the cultivar: lavender blue, pink, purple-red or white.

Roots

Fibrous roots with short rhizomes: the clump spreads slowly and divides easily.

Flowering: August–October · Plants: March–May and September · Pruning: March

Why grow it?

• Flowers from August to October and brings colour to the border when summer bloomers fade.
• Bees, bumblebees and butterflies love it: one of the last nectar sources of the year.
• Stays low and compact without pruning or staking, ideal for the front of the border.
• Looks great in pots, containers and along paths.
• Fully hardy and long-lived if you divide it every two or three years.

Bushy aster: where does it grow best?

• Full sun gives the richest flowering and the most compact growth.
• Ordinary garden soil: sand, loam or clay, acid to chalky; it is not fussy.
• Reasonably moist soil; it dislikes sitting in wet ground over winter.
• Space plants 40–50 cm apart, ideally in groups of three or five.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

0.4 m tall, 0.45 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Ornamental grasses: Plumes and fine grasses beside the little stars add movement.
• Stonecrop: The same autumn flowering, with broad, fleshy flower heads.
• Japanese anemone: Flowers at the same time, in pink and white.
• Heliopsis: Yellow flowers beside the blue and pink asters.
• Lavender: A low, grey neighbour that is still flowering in late summer.

Bushy aster: when and how to plant it?

Plant in March–May and September.

1. Plant between March and May or in September, when the soil is neither frozen nor waterlogged.
2. Dig a hole slightly wider than the root ball and mix in a little compost.
3. Set the plant at the same depth as in its pot and firm the soil well.
4. Leave 40–50 cm between plants.
5. Water thoroughly straight away and keep watering in dry spells during the first year.
6. Spread a thin layer of compost or fine bark around the base, keeping it clear of the crown.

Care

Water

Water in long dry spells during the first year. After that rain is enough, except in very dry summers and in pots.

Feeding

A spadeful of compost in spring is enough. Too much feed gives soft growth and more mildew.

Mulching

A thin layer of compost in spring keeps the soil moist. Keep the crown itself clear.

Pinching

Pinch out the shoot tips by a few centimetres at the end of May for an even denser cushion. This is optional.

Dividing

Divide the clump every two or three years in spring, otherwise the centre goes bare and flowering declines.

Tip: Divide the clump every two or three years in spring: you keep it vigorous and get free new plants. Replant the pieces in a sunny, well-drained spot.

Bushy aster: when to prune it?

Pruning months: March.

When: From late February to March, before the new shoots appear.

How:

• Cut the old, dead stems down to 5–10 cm above the ground.
• Leave the seedheads standing until then: they look good in winter and feed birds.
• If you like, pinch the tips at the end of May for a denser cushion and slightly later flowering.
• Clear dead leaves from around the base to reduce mildew.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or in September: lift the clump, split it into hand-sized pieces with roots and replant straight away. Discard the bare centre.

Cuttings

In May: take 5–8 cm cuttings from young shoots and root them in moist cutting compost in a bright spot. They root within a few weeks.

Bushy aster: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: no protection is needed in Belgian winters.
• Leave the stems standing until spring: they protect the crown and shelter insects.
• In a pot: stand it against a sheltered wall and wrap the pot in bubble wrap or hessian so the roots do not freeze. Make sure the pot does not stand in water.

Diseases and pests

• Powdery mildew: White powder on the leaves, especially in dry, stuffy summers. Plant with enough space, water in dry spells and cut off affected stems. Clear fallen leaves in spring.
• Slugs: Young shoots are eaten bare in spring. Collect slugs in the evening or set a trap.
• Bare centre: After a few years the middle of the clump dies out. Divide the plant and replant the young outer pieces.
• Shoots wilting: Waterlogged soil or a fungus can make shoots collapse suddenly. Ensure good drainage and cut off affected stems.

Through the year

• March: Cut old stems back to 5–10 cm. Divide the clump. Plant.
• April: Plant or move. Give compost.
• May: Plant. Pinch the shoot tips if you like. Watch for slugs.
• June: Growth. Water in dry spells.
• August: Flowering begins.
• September: Full flower, bees and butterflies visit for the nectar. Plant.
• October: Last flowers. Leave the seedheads.
• November: Nothing to do. Leave the stems for insects and birds.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The word aster comes from the Greek word for ‘star’, after the shape of the flowers.
• Many North American asters, this one included, were moved from the genus Aster to Symphyotrichum in 1995; in garden centres you often still find them under the old name.
• Autumn asters are an important late nectar source for bees, bumblebees and butterflies.