Cold hardiness & minimum temperature

Is Woolly Bear Begonia (Begonia leptotricha)cold hardy? Hardiness zone & min temp

Also called Woolly bear begonia, Manda's woolly bear begonia.

More about woolly bear begonia

About Woolly Bear Begonia

Begonia leptotricha · also called Woolly bear begonia, Manda's woolly bear begonia · tropical

Begonia leptotricha (also classified as Begonia subvillosa var. leptotricha by the RHS) is a South American species prized for its large, heart-shaped leaves covered in a dense coat of fine soft hairs, giving them a woolly texture that justifies its common name. It originates from humid, shaded forest habitats and produces small white flowers on hairy stems. The densely hairy leaves make it especially sensitive to overhead watering, as trapped moisture promotes fungal disease. Begonia is listed as toxic to cats, dogs, and horses by the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (16–26°C)

What woolly bear begonia's hardiness rating actually means

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

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

Woolly Bear Begonia hardiness — frequently asked questions

Is woolly bear begonia cold hardy?

Woolly Bear 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. Woolly Bear 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 woolly bear begonia can survive?

What hardiness zone is woolly bear begonia?

Woolly Bear 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 woolly bear 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 woolly bear 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.