Cold hardiness & minimum temperature

Is Temple Bells (Smithiantha cinnabarina)cold hardy? Hardiness zone & min temp

Also called Temple Bells, Cinnabarina Temple Bells.

More about temple bells

About Temple Bells

Smithiantha cinnabarina · also called Temple Bells, Cinnabarina Temple Bells · houseplant

A rhizomatous gesneriad from Mexican cloud forests bearing scarlet, tubular bell flowers on velvety stems from late summer into autumn. It enters a dry winter dormancy, dying back to scaly rhizomes, then resurges in spring. Grow it in bright, filtered light with high humidity and a peat-perlite mix — treat it like a warm, moisture-loving African violet.

Cold limit: USDA 11–12 · RHS H1a (18–25°C (growing); 10–12°C (dormancy))

Watch for — Leaf spotting: Brown or yellow spots appear when cold or hard water contacts the hairy leaves. Always water at the base with tepid, soft water.

What temple bells's hardiness rating actually means

Temple Bells 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 11–12 — 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 above about 15 °C (warm, never cold). Temple Bells has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for temple bells as it gets too cold:

Below about above about 15 °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 temple bells go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 temple bells can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Temple Bells hardiness — frequently asked questions

Is temple bells cold hardy?

Temple Bells 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. Temple Bells can only live outside year-round in genuinely frost-free climates (roughly USDA 11–12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature temple bells can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Temple Bells has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is temple bells?

Temple Bells is rated USDA 11–12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can temple bells survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 temple bells below its minimum temperature?

Below about above about 15 °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.