Cold hardiness & minimum temperature

Is Gypsum Butterwort (Pinguicula gypsicola)cold hardy? Hardiness zone & min temp

Also called Gypsum butterwort, Mexican butterwort.

More about gypsum butterwort

About Gypsum Butterwort

Pinguicula gypsicola · also called Gypsum butterwort, Mexican butterwort · houseplant

Pinguicula gypsicola is a lithophytic carnivorous plant endemic to the state of San Luis Potosí, Mexico, where it colonises gypsum rock outcrops and cliffs in semi-arid scrub alongside cacti, agaves, and Hechtia. It is a heterophyllous species, producing upright, strap-like sticky carnivorous leaves in summer and a tight succulent rosette of non-carnivorous leaves in winter — the most important care fact is that winter watering must be nearly eliminated or the plant will rot. It is not confirmed on the ASPCA non-toxic plant list and carries a precautionary mildly-toxic rating.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1c (10-30°C)

Watch for — Crown rot in winter: The most common cause of death; switching to the succulent form requires near-dry conditions. As soon as the carnivorous leaves shrivel and the tight winter rosette appears, stop tray watering immediately and only mist occasionally.

What gypsum butterwort's hardiness rating actually means

Gypsum Butterwort is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-12 (indoor in most climates) — 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 5 °C (and never frost). Gypsum Butterwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for gypsum butterwort as it gets too cold:

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can gypsum butterwort go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 gypsum butterwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Gypsum Butterwort hardiness — frequently asked questions

Is gypsum butterwort cold hardy?

Gypsum Butterwort is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Gypsum Butterwort can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature gypsum butterwort can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Gypsum Butterwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is gypsum butterwort?

Gypsum Butterwort is rated USDA 10-12 (indoor in most climates) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can gypsum butterwort survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to gypsum butterwort below its minimum temperature?

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.