Overwintering guide
How to overwinter eryngium × zabelii 'big blue'
Winter watering
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
The mistake that kills eryngium × zabelii 'big blue' in winter
Cutting eryngium × zabelii 'big blue' 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 eryngium × zabelii 'big blue' care
Overwintering eryngium × zabelii 'big blue' — FAQ
Does eryngium × zabelii 'big blue' need to come indoors for winter?
Eryngium × zabelii 'Big Blue' is hardy to roughly USDA zone 4 — winter lows around -34°C. That means it can stay outside all winter in most temperate gardens. Eryngium × zabelii 'Big Blue' 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 eryngium × zabelii 'big blue' for winter?
Tidy and mulch in late autumn; leave the plant undisturbed until spring.
How often should I water eryngium × zabelii 'big blue' in winter?
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
What kills eryngium × zabelii 'big blue' over winter?
Cutting eryngium × zabelii 'big blue' 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.