Cold hardiness & minimum temperature

Is Spotted Goldfish Plant (Nematanthus maculatus)cold hardy? Hardiness zone & min temp

Also called Spotted Goldfish Plant, Spotted Nematanthus.

More about spotted goldfish plant

About Spotted Goldfish Plant

Nematanthus maculatus · also called Spotted Goldfish Plant, Spotted Nematanthus · tropical

Nematanthus maculatus is an epiphytic gesneriad from southeastern and southern Brazil, distinguishable from other goldfish plants by spotted or mottled markings on its flowers or foliage that give rise to the common name (maculatus meaning 'spotted' in Latin). It grows in the humid, shaded branches of the Atlantic Forest and shares the family's preference for warm, bright, and humid indoor conditions. Like all Nematanthus, it produces characteristic pouch-like flowers — typically orange or red — that resemble tiny goldfish in shape. 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)

What spotted goldfish plant's hardiness rating actually means

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

Concretely, for spotted 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 spotted 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 spotted 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.

Spotted Goldfish Plant hardiness — frequently asked questions

Is spotted goldfish plant cold hardy?

Spotted 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. Spotted 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 spotted goldfish plant can survive?

What hardiness zone is spotted goldfish plant?

Spotted 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 spotted 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 spotted 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.