Cold hardiness & minimum temperature

Is Bare-stemmed Sinningia (Sinningia defoliata)cold hardy? Hardiness zone & min temp

Also called Bare-stemmed Sinningia, Leafless Sinningia.

More about bare-stemmed sinningia

About Bare-stemmed Sinningia

Sinningia defoliata · also called Bare-stemmed Sinningia, Leafless Sinningia · tropical

Sinningia defoliata is a fascinating tuberous perennial from the seasonally dry tropical biome of central Brazil, notable for its unusual flowering behaviour: the flowers emerge on separate, leaf-free stalks directly from the tuber during the dry-season rest period, before the new foliage appears in the following growing season. It carries a single large leaf (occasionally two) per vegetative shoot, with a distinctive fleshy petiole-like base. This highly specialised species is best suited to collectors of gesneriads who can mimic a seasonal dry period to trigger flowering. The ASPCA lists Sinningia (Gloxinia) as non-toxic to cats and dogs.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (16–28°C)

What bare-stemmed sinningia's hardiness rating actually means

Bare-stemmed Sinningia 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). Bare-stemmed Sinningia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Bare-stemmed Sinningia hardiness — frequently asked questions

Is bare-stemmed sinningia cold hardy?

Bare-stemmed Sinningia 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. Bare-stemmed Sinningia 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 bare-stemmed sinningia can survive?

What hardiness zone is bare-stemmed sinningia?

Bare-stemmed Sinningia 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 bare-stemmed sinningia 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 bare-stemmed sinningia 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.