Cold hardiness & minimum temperature

Is Lesser Begonia (Begonia minor)cold hardy? Hardiness zone & min temp

Also called Lesser Begonia, Small Begonia.

More about lesser begonia

About Lesser Begonia

Begonia minor · also called Lesser Begonia, Small Begonia · houseplant

Begonia minor is a compact, fibrous-rooted species native to Jamaica, producing small but plentiful pink to rosy-red flowers on upright branching stems. It thrives in bright indirect light with consistently moist, well-draining soil and appreciates moderate to high humidity. The single most important care fact is to avoid waterlogging the roots, as stem rot establishes quickly in soggy compost. All parts of Begonia minor are toxic to cats and dogs.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (13–24 °C)

What lesser begonia's hardiness rating actually means

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

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

Lesser Begonia hardiness — frequently asked questions

Is lesser begonia cold hardy?

Lesser 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. Lesser 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 lesser begonia can survive?

What hardiness zone is lesser begonia?

Lesser 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 lesser 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 lesser 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.