Cold hardiness & minimum temperature

Is Stapelia leendertziae (Stapelia leendertziae)cold hardy? Hardiness zone & min temp

Also called black bell stapelia.

More about stapelia leendertziae

About Stapelia leendertziae

Stapelia leendertziae · also called black bell stapelia · houseplant

Stapelia leendertziae, the black bell stapelia, is a striking South African stem succulent unusual among its kin for deep maroon-black, bell-shaped flowers rather than flat stars. Its soft four-angled grey-green stems clump from the base. Like other carrion flowers it lures flies with a faint foul scent, and it grows best with bright light, gritty soil, and a dry winter rest.

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

Watch for — Stem and root rot: Overwatering or cold-damp conditions turn stems soft and dark. Remove affected tissue, let it callus, and re-root healthy segments in dry, very gritty mix.

What stapelia leendertziae's hardiness rating actually means

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

Concretely, for stapelia leendertziae 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 stapelia leendertziae 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 stapelia leendertziae can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Stapelia leendertziae hardiness — frequently asked questions

Is stapelia leendertziae cold hardy?

Stapelia leendertziae 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. Stapelia leendertziae 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 stapelia leendertziae can survive?

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

What hardiness zone is stapelia leendertziae?

Stapelia leendertziae 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 stapelia leendertziae 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 stapelia leendertziae 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.