Cold hardiness & minimum temperature

Is Florist's Gloxinia (Sinningia speciosa)cold hardy? Hardiness zone & min temp

Also called Florist's gloxinia, Brazilian gloxinia, Violet slipper gloxinia, Bright eyes, Gloxinia.

More about florist's gloxinia

About Florist's Gloxinia

Sinningia speciosa · also called Florist's gloxinia, Brazilian gloxinia · flowering

Florist's gloxinia (Sinningia speciosa) is a tuberous Brazilian gesneriad grown for velvety leaves and large, bell-shaped flowers in jewel tones. Give bright indirect light, evenly moist soil, warmth and high humidity, then a dry winter rest. The ASPCA lists it as non-toxic to cats, dogs and horses.

Cold limit: USDA 11-12 (outdoors); grown as a houseplant or seasonal indoor plant in all other zones (18-24C)

Watch for — Brown spots on leaves: Caused by water sitting on the velvety foliage, especially cold water. The marks are permanent. Always water from below or directly onto the soil and keep droplets off the leaves and crown.

What florist's gloxinia's hardiness rating actually means

Florist's Gloxinia 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 11-12 (outdoors); grown as a houseplant or seasonal indoor plant in all other zones — 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). Florist's Gloxinia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Florist's Gloxinia hardiness — frequently asked questions

Is florist's gloxinia cold hardy?

Florist's Gloxinia 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. Florist's Gloxinia can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (outdoors); grown as a houseplant or seasonal indoor plant in all other zones); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature florist's gloxinia can survive?

What hardiness zone is florist's gloxinia?

Florist's Gloxinia is rated USDA 11-12 (outdoors); grown as a houseplant or seasonal indoor plant in all other zones and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can florist's gloxinia 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 florist's gloxinia 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.