Cold hardiness & minimum temperature

Is Autumn Fern (Dryopteris erythrosora)cold hardy? Hardiness zone & min temp

Also called Autumn fern, Japanese shield fern, Copper shield fern, Shaggy shield fern.

More about autumn fern

About Autumn Fern

Dryopteris erythrosora · also called Autumn fern, Japanese shield fern · houseplant

Autumn fern (Dryopteris erythrosora) is a slow-growing, semi-evergreen shade fern prized for coppery-bronze new fronds that mature to deep green. It wants bright indirect light, constantly moist organic soil, and high humidity. The ASPCA does not individually list it, so treat it as mildly toxic and check with a vet before pet exposure.

Cold limit: USDA USDA zones 5-9 (15-29 C)

What autumn fern's hardiness rating actually means

Yes — autumn fern is genuinely cold hardy. Rated RHS H6 and USDA USDA zones 5-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA USDA zones 5-9 — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about −20 to −15 °C. Autumn Fern is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for autumn fern as it gets too cold:

It tolerates winter lows to about −20 to −15 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can autumn fern go outside or overwinter — and where?

Plant it out within USDA USDA zones 5-9 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when autumn fern can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Autumn Fern hardiness — frequently asked questions

Is autumn fern cold hardy?

Yes — autumn fern is genuinely cold hardy. Rated RHS H6 and USDA USDA zones 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Autumn Fern is hardy across USDA USDA zones 5-9; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature autumn fern can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Autumn Fern is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is autumn fern?

Autumn Fern is rated USDA USDA zones 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can autumn fern survive winter outside?

Plant it out within USDA USDA zones 5-9 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to autumn fern below its minimum temperature?

It tolerates winter lows to about −20 to −15 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.