Italian aster

Italian aster: how do you recognise it?

Habit

Compact, upright and bushy clump 50–60 cm tall and about 45 cm wide.

Leaves

Oblong to lance-shaped, grey-green and rough with hairs.

Flower

Large star-shaped flowers 4–5 cm across in loose clusters, from August to October.

Colour

Violet-blue to lilac, also pink varieties, always with a yellow centre.

Roots

A compact, woody rootstock that does not run. Young plants are slow to root.

Flowering: August–October · Plants: April–May · Pruning: March

Why grow it?

• Flowers from August into October, when the summer border is past its best.
• An important late-season nectar source for butterflies, bees and bumblebees.
• Compact and sturdy: it does not spread and rarely flops.
• Tolerates drought and loves lime: ideal for a dry, sunny border or gravel garden.
• Rarely affected by powdery mildew, unlike many Michaelmas daisies.
• A lovely cut flower that lasts well in a vase.

Italian aster: where does it grow best?

• Full sun: in shade the stems go floppy and it flowers less.
• Free-draining, poor to moderately fertile soil: sand or loam, neutral to chalky.
• Dry to moderately moist. Wet soil in winter makes it rot.
• Lovely in a dry border, a gravel garden or a steppe-style planting.
• Plant 40–45 cm apart, in groups of three or five.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

0.6 m tall, 0.45 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Ice plant: Flowers at the same time in pink and is visited by the same butterflies.
• Feather grass: Fine, swaying stems next to the compact clumps, in the same dry soil.
• Black-eyed Susan: Golden yellow next to violet-blue: a classic late-summer contrast.
• Lavender: Grey foliage and the same liking for sun, drought and lime.

Italian aster: when and how to plant it?

Plant in April–May.

1. Plant only in April–May, never in autumn: young plants are slow to root and then rot in wet winter soil.
2. Loosen the soil well and on heavier ground mix in some coarse sand or gravel.
3. On acid soil, add a handful of lime to the planting hole.
4. Set the plant at the same depth as it was in its pot, 40–45 cm apart.
5. Water straight away and again during dry spells in the first year.

Care

Water

Only in the first year during dry spells. After that it copes even in dry summers.

Feeding

Not needed. On rich soil it goes floppy; at most a thin layer of compost in spring.

Support

Usually not needed. On rich soil a few twiggy sticks around the clump help.

Cut flowers

Cut stems when half the flowers are open; they last a long time in a vase.

Dividing

Only in spring and only after 4–5 years, when the clump goes bare in the middle.

Tip: Plant and divide Italian aster only in spring and give it a sunny spot with dry, chalky soil: it will then last for years, almost free of mildew.

Italian aster: when to prune it?

Pruning months: March.

When: Cut the old stems back in March, before the new shoots start to grow. Leave them standing all winter.

How:

• Cut all dead stems down to 5–10 cm above the ground.
• During flowering, remove faded clusters if you want to keep the plant tidy.
• No other pruning is needed: it stays compact naturally.

Caution: Do not cut it back in autumn: the old stems protect the crown of the plant over winter.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In April–May: lift the clump, split it into pieces each with a few shoots and roots, and discard the woody centre. Never in autumn.

Basal cuttings

In April–May take 5–8 cm cuttings from young shoots at the base and insert them in sandy cutting compost. They root within a few weeks.

Italian aster: how does it get through the winter?

Hardy to −30 °C.

• Hardy to about −30 °C: frost is no problem.
• Wet soil in winter is: give it a free-draining spot.
• Leave the stems until March; they protect the crown of the plant.
• In a pot: provide a drainage hole and pot feet, and move the pot under cover in very wet weather.

Diseases and pests

• Winter losses: The plant fails to return in spring, usually because of wet soil or autumn planting. Plant in spring and improve drainage with grit.
• Slugs: They eat young shoots in spring. Pick them off in the evening.
• Powdery mildew: Rare, sometimes during long dry spells. Water at the base and remove affected leaves.
• Bare clump: Old clumps flower less in the middle. Divide them in spring and replant the young outer pieces.

Through the year

• March: Cut old stems back to 5–10 cm.
• April: Plant. Divide or take cuttings.
• May: Plant. Water in dry spells. Watch for slugs.
• July: Water during long dry spells, especially young plants.
• August: Flowering starts. Cut flowers for the house.
• September: In full flower and full of butterflies. Remove faded clusters.
• October: Last flowers. Leave the stems standing.
• November: No pruning and no dividing: wait until spring.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The name aster comes from the Greek word for star.
• The species name amellus goes back to the Roman poet Virgil, who described a flower of that name growing by the river Mella.
• The well-known Aster × frikartii arose in Switzerland in the early 20th century from a cross between Italian aster and Aster thomsonii.