Cold hardiness & minimum temperature

Is Long-stalk Goldfish Plant (Nematanthus longipes)cold hardy? Hardiness zone & min temp

Also called Long-stalk Goldfish Plant.

More about long-stalk goldfish plant

About Long-stalk Goldfish Plant

Nematanthus longipes · also called Long-stalk Goldfish Plant · tropical

Nematanthus longipes is an epiphytic gesneriad endemic to Brazil, distinguished within the genus by its notably long flower pedicels (stalks) from which the pouch-like, orange-red flowers hang freely below the trailing stems — a trait that gives the plant its common name and makes the blooms especially visible in hanging-basket display. Like all Nematanthus, it grows in the humid Atlantic Forest and requires warm, moist, well-lit conditions indoors. The most important care fact is providing consistently bright indirect light, without which flowering is sparse or absent. The ASPCA lists Nematanthus spp. as non-toxic to cats and dogs.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (16–25 °C)

Watch for — Bud and flower drop: Long flower pedicels make the buds particularly susceptible to drop from cold draughts, sudden temperature changes, or low humidity; maintain stable conditions and keep away from air vents and exterior doors.

What long-stalk goldfish plant's hardiness rating actually means

Long-stalk 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 10-12 (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). Long-stalk Goldfish Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for long-stalk 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 long-stalk 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 long-stalk 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.

Long-stalk Goldfish Plant hardiness — frequently asked questions

Is long-stalk goldfish plant cold hardy?

Long-stalk 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. Long-stalk Goldfish Plant 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 long-stalk goldfish plant can survive?

What hardiness zone is long-stalk goldfish plant?

Long-stalk Goldfish Plant 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 long-stalk 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 long-stalk 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.