Cold hardiness & minimum temperature

Is Notched Butterwort (Pinguicula emarginata)cold hardy? Hardiness zone & min temp

Also called Notched butterwort, Mexican butterwort.

More about notched butterwort

About Notched Butterwort

Pinguicula emarginata · also called Notched butterwort, Mexican butterwort · houseplant

Pinguicula emarginata is a carnivorous butterwort native to the cloud forests of Puebla and Veracruz, Mexico, where it grows on moist river banks and limestone rocks at 1,400-1,550 m altitude. It is distinguished by its cupped, inward-curling leaves and charming white flowers with purple veins, and in habitat it shelters beneath bromeliads and orchids in consistently moist, shaded conditions. The most important care point is to maintain higher humidity than most Mexican butterworts, reflecting its cloud forest origin. It is not confirmed as non-toxic on the ASPCA database and carries a precautionary mildly-toxic rating.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1c (10-25°C)

What notched butterwort's hardiness rating actually means

Notched 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). Notched Butterwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Notched Butterwort hardiness — frequently asked questions

Is notched butterwort cold hardy?

Notched 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. Notched 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 notched butterwort can survive?

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

What hardiness zone is notched butterwort?

Notched 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 notched 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 notched 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.