Cold hardiness & minimum temperature

Is ZZ plant (Zamioculcas zamiifolia)cold hardy? Hardiness zone & min temp

Also called Zanzibar gem, eternity plant.

About ZZ plant

Zamioculcas zamiifolia · also called Zanzibar gem, eternity plant · houseplant

ZZ plant is a near-indestructible African native that stores water in potato-like underground rhizomes. It tolerates low light, drought, and neglect and is the standard recommendation for offices and dim apartments. Mildly toxic to pets.

Zamioculcas zamiifolia is an aroid native to the forest understory and grassland margins of eastern Africa, from Kenya and Tanzania (including Zanzibar) south to Mozambique and KwaZulu-Natal, where it endures a long, pronounced dry season.

Growth is slow and flush-based: new feathery, pinnate fronds emerge as bright spears from the rhizome a few at a time, and a mature houseplant typically reaches roughly 2 to 3 feet over several years.

Cold limit: USDA 9-11 (indoor-only in most US homes) · RHS H1b (18-26°C)

Watch for — No new growth: Normal in low light or winter; otherwise check the roots.

Sources: libguides.nybg.org, bbg.org, en.wikipedia.org

What zz plant's hardiness rating actually means

ZZ plant 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 9-11 (indoor-only 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). ZZ plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

ZZ plant hardiness — frequently asked questions

Is zz plant cold hardy?

ZZ plant 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. ZZ plant can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (indoor-only in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature zz plant can survive?

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

What hardiness zone is zz plant?

ZZ plant is rated USDA 9-11 (indoor-only 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 zz plant 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 zz plant 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.