Cold hardiness & minimum temperature

Is Looking Glass Begonia (Begonia 'Looking Glass')cold hardy? Hardiness zone & min temp

Also called Looking Glass begonia, silver cane begonia.

More about looking glass begonia

About Looking Glass Begonia

Begonia 'Looking Glass' · also called Looking Glass begonia, silver cane begonia · houseplant

Begonia 'Looking Glass' is a spectacular cane-type begonia cultivar grown primarily for its large, silver-overlaid leaves accented with olive-green veins and a deep burgundy underside, creating a reflective, mirror-like effect. It is a vigorous grower that benefits from bright indirect light to maintain its distinctive metallic leaf colouring and rewards consistent warmth and humidity. The most important care principle is to water deeply but infrequently, allowing the compost to partially dry to protect the cane stems from rot. Toxic to cats and dogs per the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (16–27 °C)

What looking glass begonia's hardiness rating actually means

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

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

Looking Glass Begonia hardiness — frequently asked questions

Is looking glass begonia cold hardy?

Looking Glass 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. Looking Glass 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 looking glass begonia can survive?

What hardiness zone is looking glass begonia?

Looking Glass 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 looking glass 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 looking glass 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.