Cold hardiness & minimum temperature

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

Also called Zanzibar croton, narrow-leaf croton.

More about zanzibar croton

About Zanzibar Croton

Codiaeum variegatum 'Zanzibar' · also called Zanzibar croton, narrow-leaf croton · tropical

'Zanzibar' is a fine-textured croton with long, very narrow, grass-like leaves that arch and cascade in a fountain of green, yellow, orange, red, and burgundy. The slim foliage gives it a softer, almost ornamental-grass look. Like every croton it needs bright light to colour fully, plus warmth and humidity, and resents cold, dryness, and being moved, which prompt leaf drop.

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

Watch for — Leaf drop: Caused by relocation, cold drafts, low temperatures, or letting the soil dry out. The narrow leaves are especially quick to shed, so keep conditions stable.

What zanzibar croton's hardiness rating actually means

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

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

Zanzibar Croton hardiness — frequently asked questions

Is zanzibar croton cold hardy?

Zanzibar 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. Zanzibar 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 zanzibar croton can survive?

What hardiness zone is zanzibar croton?

Zanzibar 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 zanzibar 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 zanzibar 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.