Cold hardiness & minimum temperature

Is Hope's Cycad (Lepidozamia hopei)cold hardy? Hardiness zone & min temp

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

More about hope's cycad

About Hope's Cycad

Lepidozamia hopei · also called Hope's Cycad, Hope's Zamia · tropical

Lepidozamia hopei is one of the world's tallest cycads, native to tropical rainforest margins in Far North Queensland, Australia. Its glossy, deep-green arching fronds can reach 3 m and emerge from a stout columnar trunk. Suited to warm, humid, sheltered positions, it is a showstopper landscape specimen. All parts are severely toxic to pets and humans.

Cold limit: USDA 10-12 · RHS H1b (15–35°C)

What hope's cycad's hardiness rating actually means

Hope's Cycad 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 — 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). Hope's Cycad has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Hope's Cycad hardiness — frequently asked questions

Is hope's cycad cold hardy?

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

What is the minimum temperature hope's cycad can survive?

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

What hardiness zone is hope's cycad?

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

Can hope's cycad 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 hope's cycad 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.