Overwintering guide
How to overwinter smooth blue aster
Winter watering
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
The mistake that kills smooth blue aster in winter
Cutting smooth blue aster hard back in autumn "to tidy up". That removes the growth that shelters the crown, and on some plants removes next season's flower buds entirely.
More smooth blue aster care
Overwintering smooth blue aster — FAQ
Does smooth blue aster need to come indoors for winter?
Smooth Blue Aster is hardy to roughly USDA zone 3 — winter lows around -40°C. That means it can stay outside all winter in most temperate gardens. Smooth Blue Aster is properly hardy and overwinters outside without fuss. Tidy away anything dead or diseased, apply a mulch over the crown to steady soil temperatures, and otherwise leave it alone — many hardy plants actually need a cold period to flower and grow well the following year. Save hard pruning for the right season rather than doing it in autumn.
When should I move smooth blue aster for winter?
Tidy and mulch in late autumn; leave the plant undisturbed until spring.
How often should I water smooth blue aster in winter?
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
What kills smooth blue aster over winter?
Cutting smooth blue aster hard back in autumn "to tidy up". That removes the growth that shelters the crown, and on some plants removes next season's flower buds entirely.