Cold hardiness & minimum temperature

Is Smooth Cane Begonia (Begonia glabra)cold hardy? Hardiness zone & min temp

Also called Smooth cane begonia, Climbing sorrel, Vining begonia.

More about smooth cane begonia

About Smooth Cane Begonia

Begonia glabra · also called Smooth cane begonia, Climbing sorrel · tropical

Begonia glabra is a scandent, climbing or trailing perennial native to humid tropical forest from southern Mexico through Central America and into northern South America, where it grows epiphytically on tree trunks and moist rock faces, reaching up to 15 m in the wild. Its smooth, succulent stems root readily at nodes and it is unusual among begonias for its vigorous climbing habit. The single most important care point is providing a support or allowing it to trail freely in a warm, humid environment — stems become leggy and weak if light is insufficient. Begonias are toxic to cats, dogs, and horses.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (18–28°C)

What smooth cane begonia's hardiness rating actually means

Smooth Cane Begonia 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). Smooth Cane Begonia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Smooth Cane Begonia hardiness — frequently asked questions

Is smooth cane begonia cold hardy?

Smooth Cane Begonia 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. Smooth Cane Begonia 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 smooth cane begonia can survive?

What hardiness zone is smooth cane begonia?

Smooth Cane Begonia 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 smooth cane begonia 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 smooth cane begonia 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.