Cold hardiness & minimum temperature

Is Blood-red Bertolonia (Bertolonia sanguinea)cold hardy? Hardiness zone & min temp

Also called Blood-red Bertolonia, Crimson Jewel Plant.

More about blood-red bertolonia

About Blood-red Bertolonia

Bertolonia sanguinea · also called Blood-red Bertolonia, Crimson Jewel Plant · tropical

Blood-red Bertolonia is a striking Brazilian tropical notable for its rich, deep crimson-red undersides and dark, velvety green upper leaf surfaces with silver striping. Native to the humid Atlantic Forest understorey, it demands terrarium conditions — high humidity, warmth, and shade — and rewards specialist growers with one of the most dramatic leaf colorations in the genus.

Cold limit: USDA 12 · RHS H1a (19–28°C)

Watch for — Loss of red underside colour: The vivid crimson pigmentation on the leaf reverse fades with excessive light or insufficient warmth. Maintain shaded indirect light and keep temperatures above 19°C year-round.

What blood-red bertolonia's hardiness rating actually means

Blood-red Bertolonia 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 12 — 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). Blood-red Bertolonia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for blood-red bertolonia 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 blood-red bertolonia 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 blood-red bertolonia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Blood-red Bertolonia hardiness — frequently asked questions

Is blood-red bertolonia cold hardy?

Blood-red Bertolonia 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. Blood-red Bertolonia can only live outside year-round in genuinely frost-free climates (roughly USDA 12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature blood-red bertolonia can survive?

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

What hardiness zone is blood-red bertolonia?

Blood-red Bertolonia is rated USDA 12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can blood-red bertolonia 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 blood-red bertolonia 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.