Cold hardiness & minimum temperature

Is Curio Rowleyanus (Curio rowleyanus)cold hardy? Hardiness zone & min temp

Also called string of pearls, rosary plant, bead plant.

More about curio rowleyanus

About Curio Rowleyanus

Curio rowleyanus · also called string of pearls, rosary plant · houseplant

Curio rowleyanus, the string of pearls, is a trailing South African succulent (formerly Senecio rowleyanus) with cascading stems of spherical, pea-like leaves, each with a translucent 'window' to harness light. Grown in hanging pots for its waterfall of beads, it needs bright light, very lean draining soil and careful, infrequent watering, as its delicate strands rot easily if kept wet.

Cold limit: USDA 9-12 (indoor in most US homes) · RHS H1c (18-26°C)

What curio rowleyanus's hardiness rating actually means

Curio Rowleyanus 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 9-12 (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). Curio Rowleyanus has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Curio Rowleyanus hardiness — frequently asked questions

Is curio rowleyanus cold hardy?

Curio Rowleyanus 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. Curio Rowleyanus can only live outside year-round in genuinely frost-free climates (roughly USDA 9-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature curio rowleyanus can survive?

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

What hardiness zone is curio rowleyanus?

Curio Rowleyanus is rated USDA 9-12 (indoor in most US homes) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can curio rowleyanus 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 curio rowleyanus 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.