Cold hardiness & minimum temperature

Is Colocasia 'Black Magic' (Colocasia esculenta 'Black Magic')cold hardy? Hardiness zone & min temp

Also called Black Magic elephant ear, Black taro, Black elephant ear, Imperial taro.

More about colocasia 'black magic'

About Colocasia 'Black Magic'

Colocasia esculenta 'Black Magic' · also called Black Magic elephant ear, Black taro · tropical

Colocasia 'Black Magic' is a tuberous tropical grown for its huge heart-shaped, dusky purple-black leaves. It wants bright light, constantly moist to wet soil, warmth, and high humidity, and dies back below freezing. The ASPCA lists Colocasia esculenta as toxic to dogs and cats due to insoluble calcium oxalate crystals, so keep it away from pets.

Cold limit: USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms in colder zones) (18-27°C)

Watch for — Drooping or wilting: Most often a thirst signal — the soil has dried out. In cool conditions drooping can also signal cold stress; keep it above 18°C (65°F) and consistently moist.

What colocasia 'black magic''s hardiness rating actually means

Colocasia 'Black Magic' is half-hardy (RHS H3). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H3 means: Half-hardy — comes through mild UK winters outside but is killed by a hard freeze. On the US scale that maps to USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms 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 −5 to 1 °C — a light, short frost only. Colocasia 'Black Magic' shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for colocasia 'black magic' as it gets too cold:

Down to roughly about −5 to 1 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can colocasia 'black magic' go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms in colder zones) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 colocasia 'black magic' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H3 figure above.

Frost protection for borderline colocasia 'black magic'

Colocasia 'Black Magic' is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Colocasia 'Black Magic' hardiness — frequently asked questions

Is colocasia 'black magic' cold hardy?

Colocasia 'Black Magic' is half-hardy (RHS H3). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms in colder zones) (and sheltered UK gardens) colocasia 'black magic' can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature colocasia 'black magic' can survive?

Minimum survivable temperature is roughly about −5 to 1 °C — a light, short frost only. Colocasia 'Black Magic' shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is colocasia 'black magic'?

Colocasia 'Black Magic' is rated USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms in colder zones) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can colocasia 'black magic' survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA USDA 8-10 (tubers may stay in the ground in zones 8b-10; lift and overwinter corms in colder zones) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect colocasia 'black magic' from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.