Cold hardiness & minimum temperature

Is Striped Goldfish Plant (Nematanthus strigillosus)cold hardy? Hardiness zone & min temp

Also called Striped Goldfish Plant, Downy-leaf Goldfish Plant, Goldfish Plant.

More about striped goldfish plant

About Striped Goldfish Plant

Nematanthus strigillosus · also called Striped Goldfish Plant, Downy-leaf Goldfish Plant · tropical

Nematanthus strigillosus is a trailing epiphytic gesneriad endemic to Brazil's Atlantic Forest, distinguished from other goldfish plants by its softly hairy (strigose) elliptic leaves and vibrant orange-red tubular flowers produced from spring through autumn. It grows as a hanging-basket specimen in most climates, with stems that can reach 90 cm if left unpinched. Keep it in bright indirect light and allow the top layer of compost to dry slightly between waterings to keep it blooming freely. According to the ASPCA, Nematanthus spp. is non-toxic to cats and dogs.

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

Watch for — Leaf drop after cold draughts: N. strigillosus drops leaves suddenly when exposed to cold draughts or temperatures below 13°C; keep away from single-glazed windows in winter.

What striped goldfish plant's hardiness rating actually means

Striped 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). Striped Goldfish Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for striped 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 striped 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 striped 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.

Striped Goldfish Plant hardiness — frequently asked questions

Is striped goldfish plant cold hardy?

Striped 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. Striped 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 striped goldfish plant can survive?

What hardiness zone is striped goldfish plant?

Striped 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 striped 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 striped 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.