Cold hardiness & minimum temperature

Is Three-Coloured Bladderwort (Utricularia tricolor)cold hardy? Hardiness zone & min temp

Also called Three-coloured bladderwort, Three-colored bladderwort.

More about three-coloured bladderwort

About Three-Coloured Bladderwort

Utricularia tricolor · also called Three-coloured bladderwort, Three-colored bladderwort · flowering

Utricularia tricolor is a perennial terrestrial bladderwort native to South America, found across Brazil, Argentina, Bolivia, Colombia, Paraguay, Uruguay, and Venezuela, where it grows in seasonally wet grasslands and savannas. Named for its striking three-toned flowers — purple upper lobe, white lower lip, and yellow centre — it is one of the showiest bladderworts in cultivation. The most critical care point is using only mineral-poor water such as rainwater or reverse-osmosis water. No toxicity to cats or dogs has been established for this species.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (10–30°C)

What three-coloured bladderwort's hardiness rating actually means

Three-Coloured Bladderwort 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. 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 10 °C (sustained cold below this is damaging). Three-Coloured Bladderwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for three-coloured bladderwort as it gets too cold:

Below about about 10 °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 three-coloured bladderwort go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °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 three-coloured bladderwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Three-Coloured Bladderwort hardiness — frequently asked questions

Is three-coloured bladderwort cold hardy?

Three-Coloured Bladderwort 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. Three-Coloured Bladderwort 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 three-coloured bladderwort can survive?

What hardiness zone is three-coloured bladderwort?

Three-Coloured Bladderwort is rated USDA 10-12 (indoor in most climates) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can three-coloured bladderwort survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °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 three-coloured bladderwort below its minimum temperature?

Below about about 10 °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.