Cold hardiness & minimum temperature

Is Maidenhair Spleenwort (Asplenium trichomanes)cold hardy? Hardiness zone & min temp

Also called Common maidenhair spleenwort.

More about maidenhair spleenwort

About Maidenhair Spleenwort

Asplenium trichomanes · also called Common maidenhair spleenwort · houseplant

Maidenhair spleenwort is a small, hardy evergreen fern with slender dark-brown to black wiry stems lined with neat, round, bright-green pinnae. Naturally a crevice dweller on rocks and old walls, it suits alpine pans, terrariums and cool, bright corners. Compact and tolerant of lime, it thrives where larger ferns struggle for room.

Cold limit: USDA 3-8 (hardy outdoors; grown indoors in cool rooms) · RHS H6 (10-20°C)

What maidenhair spleenwort's hardiness rating actually means

Yes — maidenhair spleenwort is genuinely cold hardy. Rated RHS H6 and USDA 3-8 (hardy outdoors; grown indoors in cool rooms), 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 3-8 (hardy outdoors; grown indoors in cool rooms) — 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. Maidenhair Spleenwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for maidenhair spleenwort 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 maidenhair spleenwort go outside or overwinter — and where?

Plant it out within USDA 3-8 (hardy outdoors; grown indoors in cool rooms) 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 maidenhair spleenwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Maidenhair Spleenwort hardiness — frequently asked questions

Is maidenhair spleenwort cold hardy?

Yes — maidenhair spleenwort is genuinely cold hardy. Rated RHS H6 and USDA 3-8 (hardy outdoors; grown indoors in cool rooms), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Maidenhair Spleenwort is hardy across USDA 3-8 (hardy outdoors; grown indoors in cool rooms); 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 maidenhair spleenwort can survive?

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

What hardiness zone is maidenhair spleenwort?

Maidenhair Spleenwort is rated USDA 3-8 (hardy outdoors; grown indoors in cool rooms) and RHS H6 — Hardy throughout the UK and northern Europe.

Can maidenhair spleenwort survive winter outside?

Plant it out within USDA 3-8 (hardy outdoors; grown indoors in cool rooms) 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 maidenhair spleenwort 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.