Cold hardiness & minimum temperature

Is Alpine Butterwort (Pinguicula alpina)cold hardy? Hardiness zone & min temp

Also called alpine butterwort, white-flowered butterwort.

More about alpine butterwort

About Alpine Butterwort

Pinguicula alpina · also called alpine butterwort, white-flowered butterwort · houseplant

Alpine butterwort is a cold-hardy temperate carnivore from European and Asian mountains, forming a flat rosette of greasy, sticky leaves that glue down small insects. It needs cool conditions, pure mineral-free water, a gritty calcareous mix, and a true winter dormancy as a resting hibernaculum. White spurred flowers appear in spring.

Cold limit: USDA 4-7 · RHS H5 (5-22°C)

Watch for — No winter dormancy: This is a temperate, cold-climate species. Kept warm year-round it fails to form its hibernaculum and gradually dies. Give it a cold (near-freezing), barely-moist winter rest.

What alpine butterwort's hardiness rating actually means

Yes — alpine butterwort is genuinely cold hardy. Rated RHS H5 and USDA 4-7, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 4-7 — 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 −15 to −10 °C. Alpine Butterwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for alpine butterwort as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 alpine butterwort go outside or overwinter — and where?

Plant it out within USDA 4-7 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 alpine butterwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Alpine Butterwort hardiness — frequently asked questions

Is alpine butterwort cold hardy?

Yes — alpine butterwort is genuinely cold hardy. Rated RHS H5 and USDA 4-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Alpine Butterwort is hardy across USDA 4-7; 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 alpine butterwort can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Alpine Butterwort is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is alpine butterwort?

Alpine Butterwort is rated USDA 4-7 and RHS H5 — Hardy in most of the UK and in cold winters.

Can alpine butterwort survive winter outside?

Plant it out within USDA 4-7 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 alpine butterwort below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.