Cold hardiness & minimum temperature

Is Long-Stalked Bladderwort (Utricularia praelonga)cold hardy? Hardiness zone & min temp

Also called Long-stalked bladderwort.

More about long-stalked bladderwort

About Long-Stalked Bladderwort

Utricularia praelonga · also called Long-stalked bladderwort · tropical

Utricularia praelonga is a perennial terrestrial bladderwort native to tropical South America (Brazil and adjacent countries), growing in sandy peat bogs and seasonally flooded meadows. It is distinctive for having two kinds of leaves — long grass-like ones and shorter strap-shaped ones — along with underground bladder traps that capture nematodes and microorganisms. Bright yellow flowers are produced on tall scapes and appear reliably in warm conditions. The most important care fact is that the substrate must remain constantly moist to wet, with the plant performing well in a shallow water tray. Utricularia is not listed in the ASPCA database; classified as mildly-toxic as a precaution.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1a (15–32°C)

What long-stalked bladderwort's hardiness rating actually means

Long-Stalked 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. 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 above about 15 °C (warm, never cold). Long-Stalked Bladderwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for long-stalked bladderwort as it gets too cold:

Below about above about 15 °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 long-stalked bladderwort go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 long-stalked bladderwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Long-Stalked Bladderwort hardiness — frequently asked questions

Is long-stalked bladderwort cold hardy?

Long-Stalked 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. Long-Stalked 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 long-stalked bladderwort can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Long-Stalked Bladderwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is long-stalked bladderwort?

Long-Stalked Bladderwort is rated USDA 10-12 (indoor in most climates) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can long-stalked bladderwort survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 long-stalked bladderwort below its minimum temperature?

Below about above about 15 °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.