Cold hardiness & minimum temperature

Is Typhonium brownii (Typhonium brownii)cold hardy? Hardiness zone & min temp

Also called Brown's typhonium.

More about typhonium brownii

About Typhonium brownii

Typhonium brownii · also called Brown's typhonium · tropical

Typhonium brownii is a small tuberous arum from rainforest creek banks of south-east Queensland and New South Wales. It throws a slender purple-brown spathe over a fly-pollinated spadix, then dies back to a dormant tuber. Grow it warm, shaded and humid in free-draining humus, keeping it barely moist while dormant.

Cold limit: USDA 10-11 (frost-tender; grow under glass or as a container plant in cooler regions) · RHS H1c (16-28°C)

Watch for — Leaf-edge browning: Low humidity or dry air scorches the thin blades. Raise humidity with grouping or a tray and keep out of heating-vent draughts.

What typhonium brownii's hardiness rating actually means

Typhonium brownii 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 10-11 (frost-tender; grow under glass or as a container plant in cooler regions) — 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). Typhonium brownii has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for typhonium brownii 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 typhonium brownii 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 typhonium brownii can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Typhonium brownii hardiness — frequently asked questions

Is typhonium brownii cold hardy?

Typhonium brownii 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. Typhonium brownii can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (frost-tender; grow under glass or as a container plant in cooler regions)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature typhonium brownii can survive?

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

What hardiness zone is typhonium brownii?

Typhonium brownii is rated USDA 10-11 (frost-tender; grow under glass or as a container plant in cooler regions) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can typhonium brownii 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 typhonium brownii 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.