Cold hardiness & minimum temperature

Is Polka dot begonia (Begonia maculata)cold hardy? Hardiness zone & min temp

Also called Polka dot begonia, Spotted begonia, Trout begonia, Begonia maculata 'Wightii', Clown begonia.

More about polka dot begonia

About Polka dot begonia

Begonia maculata · also called Polka dot begonia, Spotted begonia · tropical

Begonia maculata is a Brazilian cane begonia prized for olive leaves spotted silver above and wine-red beneath, plus clusters of white winter flowers. Its one defining need is balanced moisture: keep the mix lightly damp but never soggy, because its shallow roots rot quickly in waterlogged soil while drying out triggers fast leaf drop.

Cold limit: USDA 10-11 · RHS H1B (min 10-15°C; tender, grown under glass or indoors in the UK) (18-27°C)

Watch for — Sudden leaf drop: Lower canes shed leaves first when stressed. Cold draughts from windows, doors or AC vents, sudden temperature swings, or being moved to a new spot can trigger rapid drop. Keep it in a stable, draught-free position away from cold glass.

What polka dot begonia's hardiness rating actually means

Polka dot 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-11 — 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 5 °C (and never frost). Polka dot begonia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for polka dot begonia as it gets too cold:

Below about about 5 °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 polka dot begonia go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 polka dot begonia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Polka dot begonia hardiness — frequently asked questions

Is polka dot begonia cold hardy?

Polka dot 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. Polka dot begonia can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature polka dot begonia can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Polka dot begonia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is polka dot begonia?

Polka dot begonia is rated USDA 10-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can polka dot begonia survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 polka dot begonia below its minimum temperature?

Below about about 5 °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.