Cold hardiness & minimum temperature

Is Oersted's Columnea (Columnea oerstediana)cold hardy? Hardiness zone & min temp

Also called Oersted's Columnea, Goldfish Plant.

More about oersted's columnea

About Oersted's Columnea

Columnea oerstediana · also called Oersted's Columnea, Goldfish Plant · tropical

Columnea oerstediana is an epiphytic subshrub with a native range spanning Central America to the Guianas, growing in wet tropical forest biomes. Named in honour of the Danish botanist Anders Sandoe Oersted, it is a compact, trailing plant with small, opposite coriaceous leaves and vivid tubular flowers in red or orange borne in leaf axils from spring through autumn. It grows well in hanging baskets with bright indirect light and high humidity, and is notably tolerant of being slightly root-bound. Columnea (Gesneriaceae) is non-toxic to cats and dogs per the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (15–25 °C)

Watch for — Flower bud drop: Buds abort and fall when the plant is moved, exposed to cold draughts, or allowed to dry out suddenly. Once buds form, keep the plant in the same stable position, maintain even soil moisture, and protect from heating or air-conditioning draughts.

What oersted's columnea's hardiness rating actually means

Oersted's Columnea 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). Oersted's Columnea has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Oersted's Columnea hardiness — frequently asked questions

Is oersted's columnea cold hardy?

Oersted's Columnea 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. Oersted's Columnea 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 oersted's columnea can survive?

What hardiness zone is oersted's columnea?

Oersted's Columnea 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 oersted's columnea 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 oersted's columnea 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.