Cold hardiness & minimum temperature

Is Colocasia Crown of Tonga (Colocasia esculenta 'Crown of Tonga')cold hardy? Hardiness zone & min temp

Also called Crown of Tonga taro.

More about colocasia crown of tonga

About Colocasia Crown of Tonga

Colocasia esculenta 'Crown of Tonga' · also called Crown of Tonga taro · tropical

Colocasia esculenta 'Crown of Tonga' is a dramatic elephant ear cultivar with large heart-shaped leaves flushed deep burgundy-purple and dark veining. A fast, lush bog grower, it thrives in heat, full to part sun, and constantly moist or even boggy soil. Outdoors it is a striking seasonal feature; indoors it needs warmth, bright light and high humidity.

Cold limit: USDA 8-11 (root-hardy with mulch in zone 8; lift or store tubers in colder zones) · RHS H2 (20-30°C)

Watch for — Cold damage and dieback: Frost and cold soil kill top growth and can rot tubers. Lift and store tubers, or heavily mulch in borderline zones, bringing it in before frost.

What colocasia crown of tonga's hardiness rating actually means

Colocasia Crown of Tonga is half-hardy (RHS H2). 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 H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 8-11 (root-hardy with mulch in zone 8; lift or store tubers 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 1 to 5 °C — tolerates cold but no real frost. Colocasia Crown of Tonga shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for colocasia crown of tonga as it gets too cold:

Down to roughly about 1 to 5 °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 crown of tonga go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (root-hardy with mulch in zone 8; lift or store tubers 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 crown of tonga can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline colocasia crown of tonga

Colocasia Crown of Tonga 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 Crown of Tonga hardiness — frequently asked questions

Is colocasia crown of tonga cold hardy?

Colocasia Crown of Tonga is half-hardy (RHS H2). 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 8-11 (root-hardy with mulch in zone 8; lift or store tubers in colder zones) (and sheltered UK gardens) colocasia crown of tonga 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 crown of tonga can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Colocasia Crown of Tonga shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is colocasia crown of tonga?

Colocasia Crown of Tonga is rated USDA 8-11 (root-hardy with mulch in zone 8; lift or store tubers in colder zones) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can colocasia crown of tonga survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (root-hardy with mulch in zone 8; lift or store tubers 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 crown of tonga 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.