Cold hardiness & minimum temperature

Is Begonia Amphioxus (Begonia amphioxus)cold hardy? Hardiness zone & min temp

Also called Red Butterfly Begonia, Borneo Begonia, Star of Borneo.

More about begonia amphioxus

About Begonia Amphioxus

Begonia amphioxus · also called Red Butterfly Begonia, Borneo Begonia · houseplant

Begonia amphioxus is a compact limestone begonia from Borneo, prized for narrow lance-shaped leaves splashed with vivid red spots and margins. It thrives in bright indirect light, high humidity, and warmth — ideal for terrariums. Per the ASPCA, all Begonia species are toxic to cats, dogs, and horses, so keep it away from pets.

Cold limit: 18–30°C

Watch for — Stem and crown rot in winter: Cold, wet conditions and temperature swings cause rot. Keep it consistently warm (above ~15°C/59°F), away from cold drafts, and water more sparingly when growth slows.

What begonia amphioxus's hardiness rating actually means

Begonia Amphioxus 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 not formally rated (treat as tender) — 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). Begonia Amphioxus has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Begonia Amphioxus hardiness — frequently asked questions

Is begonia amphioxus cold hardy?

Begonia Amphioxus 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. Begonia Amphioxus can only live outside year-round in genuinely frost-free climates (roughly USDA not formally rated (treat as tender)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature begonia amphioxus can survive?

What hardiness zone is begonia amphioxus?

Begonia Amphioxus is rated USDA not formally rated (treat as tender) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can begonia amphioxus 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 begonia amphioxus 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.