Cold hardiness & minimum temperature

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

Also called Mueller's voodoo lily, porang.

More about amorphophallus muelleri

About Amorphophallus muelleri

Amorphophallus muelleri · also called Mueller's voodoo lily, porang · edible

Porang (Amorphophallus muelleri) is a tuberous Southeast Asian aroid grown commercially for glucomannan-rich corms used to make konjac flour. It produces tiny bulbils on its single umbrella leaf, allowing rapid clonal increase. The raw tuber is loaded with calcium oxalate and must be thoroughly processed before it is safe to eat.

Cold limit: USDA 10-12 (tender; lift and store the tuber dry where frost occurs) · RHS H1c (22-32°C)

Watch for — Tuber rot from overwatering: Waterlogged or cold soil in dormancy rots the corm. Keep dormant tubers dry and ensure free drainage during growth.

What amorphophallus muelleri's hardiness rating actually means

Amorphophallus muelleri 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-12 (tender; lift and store the tuber dry where frost occurs) — 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 5 °C (and never frost). Amorphophallus muelleri has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for amorphophallus muelleri as it gets too cold:

Below about about 5 °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 muelleri go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 muelleri can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Amorphophallus muelleri hardiness — frequently asked questions

Is amorphophallus muelleri cold hardy?

Amorphophallus muelleri 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 muelleri can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (tender; lift and store the tuber dry where frost occurs)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature amorphophallus muelleri can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Amorphophallus muelleri has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is amorphophallus muelleri?

Amorphophallus muelleri is rated USDA 10-12 (tender; lift and store the tuber dry where frost occurs) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can amorphophallus muelleri survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 muelleri below its minimum temperature?

Below about about 5 °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.