Cold hardiness & minimum temperature

Is Never Never Plant 'Grey Star' (Ctenanthe setosa 'Grey Star')cold hardy? Hardiness zone & min temp

Also called Never Never Plant, Grey Star, Silver-leaf Ctenanthe, Brazilian Snow Plant.

More about never never plant 'grey star'

About Never Never Plant 'Grey Star'

Ctenanthe setosa 'Grey Star' · also called Never Never Plant, Grey Star · houseplant

Ctenanthe setosa 'Grey Star' is a clumping Brazilian prayer-plant relative prized for silvery, dark-veined leaves that fold up at night. Give it bright indirect light, evenly moist soil, warmth above 12C and high humidity. It is not individually listed by the ASPCA, so treat it as mildly toxic and verify with a vet.

Cold limit: USDA 10a-12b (grown as a houseplant elsewhere; not frost hardy) (18-27C (minimum 12-13C))

What never never plant 'grey star''s hardiness rating actually means

Never Never Plant 'Grey Star' 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 10a-12b (grown as a houseplant elsewhere; not frost hardy) — 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). Never Never Plant 'Grey Star' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for never never plant 'grey star' 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 never never plant 'grey star' 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 never never plant 'grey star' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Never Never Plant 'Grey Star' hardiness — frequently asked questions

Is never never plant 'grey star' cold hardy?

Never Never Plant 'Grey Star' 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. Never Never Plant 'Grey Star' can only live outside year-round in genuinely frost-free climates (roughly USDA 10a-12b (grown as a houseplant elsewhere; not frost hardy)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature never never plant 'grey star' can survive?

What hardiness zone is never never plant 'grey star'?

Never Never Plant 'Grey Star' is rated USDA 10a-12b (grown as a houseplant elsewhere; not frost hardy) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can never never plant 'grey star' 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 never never plant 'grey star' 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.