Cold hardiness & minimum temperature

Is Amorphophallus prainii (Amorphophallus prainii)cold hardy? Hardiness zone & min temp

Also called Prain's amorphophallus, small konjac.

More about amorphophallus prainii

About Amorphophallus prainii

Amorphophallus prainii · also called Prain's amorphophallus, small konjac · tropical

Amorphophallus prainii is a Southeast Asian tuberous aroid that produces a single intricately divided leaf on a mottled snakeskin petiole each season, then dies down to a dormant corm. It needs warm, humid, brightly shaded conditions in active growth and a dry, warm rest while dormant. A compact, collectable relative of the giant konjac and titan arum.

Cold limit: USDA 10-11 (indoor or under glass in most US and UK homes) · RHS H1b (20-30°C)

Watch for — Corm rot: Cold, wet compost, especially during dormancy, rots the corm. Use a gritty free-draining mix and store the dormant corm warm and dryish.

What amorphophallus prainii's hardiness rating actually means

Amorphophallus prainii 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 10-11 (indoor or under glass in most US and UK 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). Amorphophallus prainii has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Amorphophallus prainii hardiness — frequently asked questions

Is amorphophallus prainii cold hardy?

Amorphophallus prainii 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. Amorphophallus prainii can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor or under glass in most US and UK homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature amorphophallus prainii can survive?

What hardiness zone is amorphophallus prainii?

Amorphophallus prainii is rated USDA 10-11 (indoor or under glass in most US and UK homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can amorphophallus prainii 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 amorphophallus prainii 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.