Cold hardiness & minimum temperature

Is Bullate Sinningia (Sinningia bullata)cold hardy? Hardiness zone & min temp

Also called Bullate Sinningia, Crinkle-leaf Sinningia.

More about bullate sinningia

About Bullate Sinningia

Sinningia bullata · also called Bullate Sinningia, Crinkle-leaf Sinningia · tropical

Sinningia bullata is a tuberous perennial native to southern Brazil, prized for its strikingly textured dark green bullate (pebbly, crinkled) leaves covered with dense white woolly hairs on the undersides and new shoot tips, which contrast dramatically with the bright scarlet tubular flowers. Unlike most tuberous Sinningias it does not enter a strict winter dormancy, producing new growth and flowers based on shoot maturity rather than season. It thrives in the same filtered-light conditions as African violets, making it an excellent houseplant for intermediate to warm rooms. The ASPCA lists Sinningia (Gloxinia) as non-toxic to cats and dogs.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (18–27°C)

What bullate sinningia's hardiness rating actually means

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

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

Bullate Sinningia hardiness — frequently asked questions

Is bullate sinningia cold hardy?

Bullate 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. Bullate 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 bullate sinningia can survive?

What hardiness zone is bullate sinningia?

Bullate 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 bullate 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 bullate 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.