Cold hardiness & minimum temperature

Is String of Buttons (Crassula perforata)cold hardy? Hardiness zone & min temp

Also called String of Buttons, Necklace Vine, Pagoda Plant, Stacked Crassula.

More about string of buttons

About String of Buttons

Crassula perforata · also called String of Buttons, Necklace Vine · houseplant

String of buttons is an easy, fast-growing South African succulent whose triangular leaves stack in pairs along square stems, trailing with age. Give it bright direct light, gritty fast-draining soil, and water only when bone dry. Not pet-safe: as a Crassula (jade relative) it is best treated as mildly toxic.

Cold limit: USDA 9a-12b (15-27C)

Watch for — Root rot from overwatering: Black or mushy stems and leaves that drop at a touch mean the roots are rotting. Always let soil dry fully, use gritty mix and a drained pot, and water less in winter. Salvage healthy top cuttings if the base is lost.

What string of buttons's hardiness rating actually means

String of Buttons 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 9a-12b — 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). String of Buttons has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

String of Buttons hardiness — frequently asked questions

Is string of buttons cold hardy?

String of Buttons 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. String of Buttons can only live outside year-round in genuinely frost-free climates (roughly USDA 9a-12b); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature string of buttons can survive?

What hardiness zone is string of buttons?

String of Buttons is rated USDA 9a-12b and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can string of buttons 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 string of buttons 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.