Cold hardiness & minimum temperature

Is Carnival goldfish plant (Columnea 'Carnival')cold hardy? Hardiness zone & min temp

Also called Carnival goldfish plant, Carnival columnea.

More about carnival goldfish plant

About Carnival goldfish plant

Columnea 'Carnival' · also called Carnival goldfish plant, Carnival columnea · houseplant

Columnea 'Carnival' is a floriferous hybrid gesneriad producing an almost continuous supply of crimson-and-yellow tubular flowers on woody, semi-trailing stems. A compact, low-maintenance houseplant for bright, humid rooms, it blooms in all four seasons and suits hanging baskets or a high shelf where its stems can trail freely.

Cold limit: USDA 10–11 · RHS H1b (15–27 °C)

Watch for — Bud drop: Buds fall prematurely when the plant is moved, subjected to cold draughts, or exposed to low humidity. Once flower buds appear, keep the plant in place and maintain humidity above 55%.

What carnival goldfish plant's hardiness rating actually means

Carnival goldfish plant 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 10–11 — 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). Carnival goldfish plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Carnival goldfish plant hardiness — frequently asked questions

Is carnival goldfish plant cold hardy?

Carnival goldfish plant 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. Carnival goldfish plant can only live outside year-round in genuinely frost-free climates (roughly USDA 10–11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature carnival goldfish plant can survive?

What hardiness zone is carnival goldfish plant?

Carnival goldfish plant is rated USDA 10–11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can carnival goldfish plant 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 carnival goldfish plant 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.