Cold hardiness & minimum temperature

Is Black Gold clog plant (Nematanthus 'Black Gold')cold hardy? Hardiness zone & min temp

Also called Black Gold clog plant, Black Gold goldfish plant.

More about black gold clog plant

About Black Gold clog plant

Nematanthus 'Black Gold' · also called Black Gold clog plant, Black Gold goldfish plant · houseplant

A dramatic Nematanthus hybrid cultivar distinguished by its very dark, near-black glossy foliage and brilliant gold-orange pouched flowers that provide striking contrast. An excellent hanging-basket plant that blooms prolifically in good indirect light. Like other clog plants, it needs warm, humid indoor conditions and consistent but not excessive moisture to perform at its best.

Cold limit: USDA 10–12 · RHS H1b (16–26°C)

Watch for — Bud drop: Moving the plant or exposing it to cold drafts while in bud causes flowers to drop before opening. Position in a stable, warm, draft-free spot once buds are visible.

What black gold clog plant's hardiness rating actually means

Black Gold clog 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 — 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). Black Gold clog plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Black Gold clog plant hardiness — frequently asked questions

Is black gold clog plant cold hardy?

Black Gold clog 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. Black Gold clog plant can only live outside year-round in genuinely frost-free climates (roughly USDA 10–12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature black gold clog plant can survive?

What hardiness zone is black gold clog plant?

Black Gold clog plant is rated USDA 10–12 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can black gold clog 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 black gold clog 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.