Cold hardiness & minimum temperature

Is Black Fang Begonia (Begonia 'Black Fang')cold hardy? Hardiness zone & min temp

Also called Black Fang begonia, Black Fang eyelash begonia.

More about black fang begonia

About Black Fang Begonia

Begonia 'Black Fang' · also called Black Fang begonia, Black Fang eyelash begonia · houseplant

Begonia 'Black Fang' is a striking eyelash begonia (Begonia bowerae hybrid) distinguished by its very dark, near-black, deeply lobed leaves edged with fine white eyelash hairs and accented by bright green markings along the veins, giving it a dramatic gothic appearance. It is compact and relatively easy to grow in moderate indoor conditions, producing dainty pale pink flowers in late winter that contrast beautifully with the near-black foliage. As with all rhizomatous begonias, the paramount care rule is to avoid overwatering, since the shallow rhizome is extremely sensitive to soggy compost. Toxic to cats and dogs per the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (15–26 °C)

What black fang begonia's hardiness rating actually means

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

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

Black Fang Begonia hardiness — frequently asked questions

Is black fang begonia cold hardy?

Black Fang 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. Black Fang 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 black fang begonia can survive?

What hardiness zone is black fang begonia?

Black Fang 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 black fang 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 black fang 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.