Cold hardiness & minimum temperature

Is Alocasia Macrorrhizos Giant Upright (Alocasia macrorrhizos 'Giant Upright')cold hardy? Hardiness zone & min temp

Also called Giant Upright elephant ear, upright giant taro.

More about alocasia macrorrhizos giant upright

About Alocasia Macrorrhizos Giant Upright

Alocasia macrorrhizos 'Giant Upright' · also called Giant Upright elephant ear, upright giant taro · tropical

Alocasia macrorrhizos 'Giant Upright' is a statement elephant ear that holds enormous, glossy, ribbed leaves boldly skyward on tall sturdy stems. A fast, vigorous tropical, it wants warmth, bright indirect to filtered sun, rich moist soil and high humidity. Given heat and feeding it reaches dramatic size; cold, soggy roots cause rot and decline.

Cold limit: USDA 9-11 (root-hardy with mulch at the warm edge; lift or overwinter the rhizome in colder zones) · RHS H1b (20-30°C)

Watch for — Root rot in cold, wet soil: The large rhizome rots when cold and waterlogged. Keep it warm, use a mix that drains, and cut watering back sharply over winter.

What alocasia macrorrhizos giant upright's hardiness rating actually means

Alocasia Macrorrhizos Giant Upright 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 (root-hardy with mulch at the warm edge; lift or overwinter the rhizome in colder zones) — 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). Alocasia Macrorrhizos Giant Upright has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Alocasia Macrorrhizos Giant Upright hardiness — frequently asked questions

Is alocasia macrorrhizos giant upright cold hardy?

Alocasia Macrorrhizos Giant Upright 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. Alocasia Macrorrhizos Giant Upright can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (root-hardy with mulch at the warm edge; lift or overwinter the rhizome in colder zones)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature alocasia macrorrhizos giant upright can survive?

What hardiness zone is alocasia macrorrhizos giant upright?

Alocasia Macrorrhizos Giant Upright is rated USDA 9-11 (root-hardy with mulch at the warm edge; lift or overwinter the rhizome in colder zones) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can alocasia macrorrhizos giant upright 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 alocasia macrorrhizos giant upright 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.