Overwintering guide
How to overwinter blue boy cornflower
Winter watering
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
The mistake that kills blue boy cornflower in winter
Cutting blue boy cornflower 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 blue boy cornflower care
Overwintering blue boy cornflower — FAQ
Does blue boy cornflower need to come indoors for winter?
Blue Boy cornflower is hardy to roughly USDA zone 2 — winter lows around -46°C. That means it can stay outside all winter in most temperate gardens. Blue Boy cornflower 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 blue boy cornflower for winter?
Tidy and mulch in late autumn; leave the plant undisturbed until spring.
How often should I water blue boy cornflower in winter?
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
What kills blue boy cornflower over winter?
Cutting blue boy cornflower 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.