Cold hardiness & minimum temperature

Is Euphorbia lactea 'White Ghost' (Euphorbia lactea 'White Ghost')cold hardy? Hardiness zone & min temp

Also called white ghost euphorbia, ghost cactus.

More about euphorbia lactea 'white ghost'

About Euphorbia lactea 'White Ghost'

Euphorbia lactea 'White Ghost' · also called white ghost euphorbia, ghost cactus · houseplant

Euphorbia lactea 'White Ghost' is a near-albino cultivar prized for its ghostly white, candelabra-branched stems with faint grey marbling. Lacking chlorophyll in much of its tissue, it grows slowly and needs strong light to survive. Treat it as a desert succulent: gritty soil, sparing water, and warmth above 10C year-round.

Cold limit: USDA 10-11 (indoor in most US and UK homes) · RHS H1c (18-27C)

Watch for — Cold damage: Below about 10C the stems can soften, discolour and collapse. Keep away from cold windowsills and draughts in winter and never let it freeze.

What euphorbia lactea 'white ghost''s hardiness rating actually means

Euphorbia lactea 'White Ghost' 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 and UK 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 lactea 'White Ghost' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for euphorbia lactea 'white ghost' 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 lactea 'white ghost' 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 lactea 'white ghost' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Euphorbia lactea 'White Ghost' hardiness — frequently asked questions

Is euphorbia lactea 'white ghost' cold hardy?

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

What is the minimum temperature euphorbia lactea 'white ghost' can survive?

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

What hardiness zone is euphorbia lactea 'white ghost'?

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

Can euphorbia lactea 'white ghost' 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 lactea 'white ghost' 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.