Cold hardiness & minimum temperature

Is Skinner's Zamia (Zamia skinneri)cold hardy? Hardiness zone & min temp

Also called Skinner's Zamia, Skinner's Cycad.

More about skinner's zamia

About Skinner's Zamia

Zamia skinneri · also called Skinner's Zamia, Skinner's Cycad · tropical

Zamia skinneri is a robust, large-leaved cycad native to the humid tropical forests of Costa Rica, Panama, and Colombia, where it grows as an understorey plant in deep shade. It produces broad, glossy dark-green pinnate fronds and tolerates lower light than many cycads, making it useful for shaded tropical gardens. The single most important care fact is maintaining high, consistent humidity and never allowing it to dry out completely. All parts are severely toxic to pets and humans.

Cold limit: USDA 10b–12 · RHS H1b (18–32°C)

What skinner's zamia's hardiness rating actually means

Skinner's Zamia 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 10b–12 — 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). Skinner's Zamia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Skinner's Zamia hardiness — frequently asked questions

Is skinner's zamia cold hardy?

Skinner's Zamia 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. Skinner's Zamia can only live outside year-round in genuinely frost-free climates (roughly USDA 10b–12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature skinner's zamia can survive?

What hardiness zone is skinner's zamia?

Skinner's Zamia is rated USDA 10b–12 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can skinner's zamia 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 skinner's zamia 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.