Overwintering guide
How to overwinter river water fern
Winter watering
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
The mistake that kills river water fern in winter
Cutting river water fern 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 river water fern care
Overwintering river water fern — FAQ
Does river water fern need to come indoors for winter?
River Water Fern is hardy to roughly USDA zone 5 — winter lows around -29°C. That means it can stay outside all winter in most temperate gardens. River Water Fern 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 river water fern for winter?
Tidy and mulch in late autumn; leave the plant undisturbed until spring.
How often should I water river water fern in winter?
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
What kills river water fern over winter?
Cutting river water fern 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.