Cold hardiness & minimum temperature

Is Scharff's Begonia (Begonia scharffiana)cold hardy? Hardiness zone & min temp

Also called Scharff's begonia, Hairy begonia.

More about scharff's begonia

About Scharff's Begonia

Begonia scharffiana · also called Scharff's begonia, Hairy begonia · houseplant

Begonia scharffiana is a cane-type begonia from Brazil with distinctive olive-green leaves covered in soft white hairs and bearing clusters of white to pale-pink flowers. It is a robust, fast-growing species that tolerates typical indoor conditions better than many begonias, making it a good choice for beginners. The most important care fact is to ensure strong, indirect light; without adequate brightness it becomes leggy and fails to flower reliably. This plant is toxic to cats and dogs.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (15–27 °C)

What scharff's begonia's hardiness rating actually means

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

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

Scharff's Begonia hardiness — frequently asked questions

Is scharff's begonia cold hardy?

Scharff's 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. Scharff's 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 scharff's begonia can survive?

What hardiness zone is scharff's begonia?

Scharff's 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 scharff's 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 scharff's 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.