Cold hardiness & minimum temperature

Is Fringed Caralluma (Caralluma fimbriata)cold hardy? Hardiness zone & min temp

Also called Fringed Caralluma, Caralluma.

More about fringed caralluma

About Fringed Caralluma

Caralluma fimbriata · also called Fringed Caralluma, Caralluma · houseplant

Caralluma fimbriata is a fleshy, leafless succulent from India and Sri Lanka with four-angled, mottled grey-green stems bearing small teeth. Clusters of small, fringed, dark maroon star-shaped flowers with a mild unpleasant odour appear in summer. Widely noted in traditional medicine and as a studied appetite suppressant, though clinical evidence remains mixed.

Cold limit: USDA 10-12 · RHS H1b (12–38°C)

Watch for — Etiolation in winter: Low winter light causes stems to stretch and pale. Supplement with a grow light or move to the brightest window. Etiolated growth can be cut back in spring to encourage compact regrowth.

What fringed caralluma's hardiness rating actually means

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

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

Fringed Caralluma hardiness — frequently asked questions

Is fringed caralluma cold hardy?

Fringed Caralluma 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. Fringed Caralluma 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 fringed caralluma can survive?

What hardiness zone is fringed caralluma?

Fringed Caralluma 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 fringed caralluma 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 fringed caralluma 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.