Calico aster
Symphyotrichum lateriflorum · Asteraceae
The gardener's calendar
Ideal time to plant calico aster: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Scientific name
- Symphyotrichum lateriflorum
- Family
- Asteraceae
- Type
- Perennial herbaceous plant
- Blooming period
- September to November
- Mature size
- 60 to 120 cm in height
- Foliage
- Deciduous
- Hardiness
- Very hardy (down to -20 °C)
- Origin
- North America
Care
Light exposure
Place your side-flowering aster in full sun or partial shade for optimal blooming. A minimum of 4 to 6 hours of direct daily light encourages nice branching and an abundance of small flowers. In full shade, the plant will become leggy and flower less prolifically.
Watering
Water regularly during growth and flowering, keeping the soil moist but not waterlogged. Once established, the plant tolerates moderate drought. Reduce watering in winter when the foliage disappears.
Soil and planting
Side-flowering aster adapts to most well-drained soils, even poor or slightly alkaline ones. Avoid permanently wet soils, which can cause fungal diseases. A compost addition at planting time is sufficient.
Pruning and training
Pinch young stems in late spring to encourage compact branching and more flowers. In autumn after blooming, leave the stems in place to provide shelter for beneficial insects. Cut back to ground level in late winter before new growth begins.
Fertilizing
A balanced fertilizer application in spring is usually sufficient. Avoid excess nitrogen, which would promote foliage at the expense of flowering. In poor soil, a surface mulch of compost in spring provides the necessary nutrients.
Pests and diseases
Side-flowering aster is relatively pest-resistant. The main risk is powdery mildew in cases of stagnant humidity combined with poor air circulation. Ensure good drainage and adequate spacing between plants to prevent fungal problems.
Did you know?
This aster earns the nickname "side-flowering aster" because its tiny white or pale pink flowers bloom in lateral cascades along the stems, creating a very sought-after cloudy effect by florists. In North America, it's an essential nectar plant for Monarch butterflies during their autumn migration to Mexico.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
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- YarrowAchillea millefolium
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- SneezewortAchillea ptarmica
- Canadian goldenrodSolidago canadensis
- WormwoodArtemisia absinthium
Tips generated and checked by Viridia — adapt them to your local climate.