Cold hardiness & minimum temperature

Is Woolly Sinningia (Sinningia canescens)cold hardy? Hardiness zone & min temp

Also called Woolly Sinningia, Brazilian Edelweiss, Queen of the Abyss, Silver Sinningia.

More about woolly sinningia

About Woolly Sinningia

Sinningia canescens · also called Woolly Sinningia, Brazilian Edelweiss · tropical

Sinningia canescens is an upright tuberous perennial from the rocky habitats of Brazil, valued both for its silver-white woolly stems and oval leaves and for its clusters of salmon-red tubular flowers produced in summer. The dense felting of fine hairs gives it an appearance reminiscent of Alpine edelweiss, earning it the common name Brazilian Edelweiss. It enters a dormancy period in autumn when leaves drop, and the tuber should be kept cool and barely moist over winter before restarting growth in spring. The ASPCA lists Sinningia (Gloxinia) as non-toxic to cats and dogs.

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

Watch for — Tuber rot in dormancy: The most dangerous period is winter dormancy — if kept too wet without foliage to absorb moisture, the tuber quickly rots; store in barely moist sand or compost in a cool, frost-free spot.

What woolly sinningia's hardiness rating actually means

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

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

Woolly Sinningia hardiness — frequently asked questions

Is woolly sinningia cold hardy?

Woolly 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. Woolly 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 woolly sinningia can survive?

What hardiness zone is woolly sinningia?

Woolly 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 woolly 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 woolly 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.