Cold hardiness & minimum temperature

Is Painted Begonia (Begonia picta)cold hardy? Hardiness zone & min temp

Also called Painted begonia, Himalayan begonia.

More about painted begonia

About Painted Begonia

Begonia picta · also called Painted begonia, Himalayan begonia · tropical

Begonia picta is a fibrous-rooted or weakly rhizomatous species native to the Himalayan foothills of Nepal, Bhutan, and northeastern India, where it grows on shaded, moist rock ledges and forest banks at elevations of 1,000–2,500 m. The leaves are dark green with conspicuous silvery-white spots or blotches that give the plant its 'painted' common name, and the small flowers are white to pale pink. Its montane origin means it tolerates slightly cooler temperatures than many tropical begonias, making it somewhat more adaptable to British interiors. The ASPCA lists Begonia species as toxic to cats, dogs, and horses.

Cold limit: USDA 10–12 (indoor in most climates) · RHS H1b (12–24°C)

Watch for — Root rot in winter: In cool, lower-light winter conditions, the compost stays moist for longer and root rot can develop quickly. Reduce watering frequency significantly in autumn and winter, and avoid placing the pot on cold window ledges in frosty weather.

What painted begonia's hardiness rating actually means

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

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

Painted Begonia hardiness — frequently asked questions

Is painted begonia cold hardy?

Painted 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. Painted 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 painted begonia can survive?

What hardiness zone is painted begonia?

Painted 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 painted 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 painted 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.