Aster
Keep soil consistently moist in the first season — mildew problems are worse on stressed, dry-rooted plants.
Care
Full sun to light part shade.
Standard border watering.
Fertile, moisture-retentive but well-drained soil.
Cut back to ground level in late autumn/winter once foliage has died back; divide congested clumps every 2-3 years to maintain vigour and reduce mildew.
A light balanced feed with a compost mulch as growth starts is enough. A rich diet gives tall soft stems that flop just as the flowers open, which is the opposite of what this plant is for.
Divide the clump every two or three years in spring, keeping the vigorous young growth from the outside and throwing away the woody, bare centre. Division is maintenance as much as propagation here — an undivided clump loses vigour and gets more mildew.
Month by month
Months change with the climate: in southern Italy tomatoes go out two months earlier than in England.
- MarchDivide congested clumps every 2-3 years. how ›
- MayStake tall varieties before they need it. how ›
- SeptemberMain flowering season — a valuable late nectar source.
- NovemberCut back to ground level once foliage has died back. how ›
Months based on climate: UK. Your choice stays on this device.
- MarchDivide congested clumps every 2-3 years. how ›
- MayStake tall varieties before they need it. how ›
- SeptemberMain flowering season — a valuable late nectar source.
- NovemberCut back to ground level once foliage has died back. how ›
Months based on climate: Northern Italy. Your choice stays on this device.
- FebruaryDivide congested clumps every 2-3 years. how ›
- AprilStake tall varieties before they need it. how ›
- SeptemberMain flowering season — a valuable late nectar source.
- NovemberCut back to ground level once foliage has died back. how ›
Months based on climate: Central Italy. Your choice stays on this device.
- FebruaryDivide congested clumps every 2-3 years. how ›
- AprilStake tall varieties before they need it. how ›
- SeptemberMain flowering season — a valuable late nectar source.
- DecemberCut back to ground level once foliage has died back. how ›
Months based on climate: Southern Italy and islands. Your choice stays on this device.
Common problems
How to spot it. Classic problem for this genus, worse in dry soil.
What to do. Keep soil moist, choose resistant varieties, divide regularly.
How to spot it. On young shoots.
What to do. Protect emerging growth.
How to spot it. Sudden wilting or death.
What to do. Remove and dispose of affected plants; avoid replanting in the same spot.
Popular varieties
Questions
Aster: is it hardy?
H7: Fully hardy anywhere in the UK. It survives below −20 °C.
Can it grow in a pot?
For compact varieties.
Aster: when do you prune it?
Cut back to ground level in late autumn/winter once foliage has died back; divide congested clumps every 2-3 years to maintain vigour and reduce mildew. In the calendar for UK, pruning falls in November.
Aster: when does it flower?
In the climate of UK it flowers in September–October.
When do you feed it?
A light balanced feed with a compost mulch as growth starts is enough. A rich diet gives tall soft stems that flop just as the flowers open, which is the opposite of what this plant is for. Feeding months, UK: April.