Cold hardiness & minimum temperature

Is Euphorbia gorgonis (Euphorbia gorgonis)cold hardy? Hardiness zone & min temp

Also called gorgon's head euphorbia.

More about euphorbia gorgonis

About Euphorbia gorgonis

Euphorbia gorgonis · also called gorgon's head euphorbia · houseplant

Euphorbia gorgonis, the gorgon's head, is a South African medusoid succulent: a fat central body crowned by a ring of radiating, snake-like tuberculate arms. It is forgiving for a Euphorbia, asking for bright light, a gritty mix and sparse water. The milky sap is irritant, so glove up. A characterful, slow, architectural succulent for a sunny sill.

Cold limit: USDA 10-11 (indoor in most US homes) · RHS H1c (18-30°C)

Watch for — Caudex rot: A soft, darkening central body signals overwatering or poor drainage. Use a sharply draining mix, water sparingly, and keep nearly dry in winter.

What euphorbia gorgonis's hardiness rating actually means

Euphorbia gorgonis 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-11 (indoor in most US homes) — 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 5 °C (and never frost). Euphorbia gorgonis has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for euphorbia gorgonis as it gets too cold:

Below about about 5 °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 euphorbia gorgonis go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 euphorbia gorgonis can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Euphorbia gorgonis hardiness — frequently asked questions

Is euphorbia gorgonis cold hardy?

Euphorbia gorgonis 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. Euphorbia gorgonis can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature euphorbia gorgonis can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Euphorbia gorgonis has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is euphorbia gorgonis?

Euphorbia gorgonis is rated USDA 10-11 (indoor in most US homes) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can euphorbia gorgonis survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 euphorbia gorgonis below its minimum temperature?

Below about about 5 °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.