Cold hardiness & minimum temperature

Is Quelch's Bladderwort (Utricularia quelchii)cold hardy? Hardiness zone & min temp

Also called Quelch's bladderwort, Tepui bladderwort.

More about quelch's bladderwort

About Quelch's Bladderwort

Utricularia quelchii · also called Quelch's bladderwort, Tepui bladderwort · tropical

Utricularia quelchii is a spectacular epiphytic bladderwort endemic to the tepui table-mountains of Venezuela and the Guiana Highlands, typically growing in bromeliad leaf-axils and wet moss at altitudes of 1,400–2,800 m. It is prized in cultivation for its large, orchid-like scarlet-to-orange-red flowers and is relatively easy to grow compared to other high-altitude Utricularia. Grow it in pure sphagnum at cool to intermediate temperatures with high humidity — replicating the cool, misty tepui environment is the key to success. Utricularia is not listed on the ASPCA database; classified as mildly-toxic pending formal listing.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (10–25°C)

Watch for — Heat stress from temperatures above 28°C: This high-altitude species cannot tolerate warm indoor temperatures typical of lowland homes in summer. Above 28°C growth stalls and leaves yellow; move to a cool basement, greenhouse, or air-conditioned space, targeting daytime maxima below 25°C.

What quelch's bladderwort's hardiness rating actually means

Quelch's 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). Quelch's Bladderwort has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for quelch's 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 quelch's 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 quelch's bladderwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Quelch's Bladderwort hardiness — frequently asked questions

Is quelch's bladderwort cold hardy?

Quelch's 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. Quelch's 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 quelch's bladderwort can survive?

What hardiness zone is quelch's bladderwort?

Quelch's 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 quelch's 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 quelch's 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.