Cold hardiness & minimum temperature

Is Mammy Croton (Codiaeum variegatum 'Mammy')cold hardy? Hardiness zone & min temp

Also called Mammy croton, curly croton.

More about mammy croton

About Mammy Croton

Codiaeum variegatum 'Mammy' · also called Mammy croton, curly croton · tropical

'Mammy' is a striking croton with narrow, twisting and curling leaves that spiral down the stem in shifting bands of green, yellow, red, and purple. The corkscrew foliage makes it one of the most ornamental cultivars. Like all crotons it craves bright light, warmth, and humidity, and resents sudden change, dropping leaves if chilled, moved, or allowed to dry out.

Cold limit: USDA 10-12 (indoor in most US homes) · RHS H1b (18-29°C)

Watch for — Leaf drop after a move: Crotons shed leaves in response to relocation, drafts, cold, or drying out. Keep its position and watering stable, and expect some drop when first settling in.

What mammy croton's hardiness rating actually means

Mammy Croton 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 (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 10 °C (sustained cold below this is damaging). Mammy Croton has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Mammy Croton hardiness — frequently asked questions

Is mammy croton cold hardy?

Mammy Croton 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. Mammy Croton can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature mammy croton can survive?

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Mammy Croton has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is mammy croton?

Mammy Croton is rated USDA 10-12 (indoor in most US homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can mammy croton 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 mammy croton 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.