Cold hardiness & minimum temperature

Is Roxburgh's Typhonium (Typhonium roxburghii)cold hardy? Hardiness zone & min temp

Also called Roxburgh's Rodent Arum, Typhonium.

More about roxburgh's typhonium

About Roxburgh's Typhonium

Typhonium roxburghii · also called Roxburgh's Rodent Arum, Typhonium · tropical

Typhonium roxburghii is a small tuberous aroid from tropical and subtropical Asia, producing arrow-shaped leaves and a slender spathe inflorescence in spring. It is a botanically interesting rather than decorative species, grown by aroid collectors. Contains calcium oxalates common to all Araceae; toxic to pets.

Cold limit: USDA 9–11 (may survive mild winters outdoors with mulch; better lifted in colder zones) · RHS H3 (15–30°C)

Watch for — Tuber rot in winter: Leaving tubers in wet soil over the dormant period causes rot. Ensure the compost is dry from leaf die-back until spring re-emergence, or lift and store tubers in dry sand or paper bags.

What roxburgh's typhonium's hardiness rating actually means

Roxburgh's Typhonium 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 9–11 (may survive mild winters outdoors with mulch; better lifted 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. Roxburgh's Typhonium shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for roxburgh's typhonium 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 roxburgh's typhonium go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9–11 (may survive mild winters outdoors with mulch; better lifted 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 roxburgh's typhonium 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 roxburgh's typhonium

Roxburgh's Typhonium 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.

Roxburgh's Typhonium hardiness — frequently asked questions

Is roxburgh's typhonium cold hardy?

Roxburgh's Typhonium 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 9–11 (may survive mild winters outdoors with mulch; better lifted in colder zones) (and sheltered UK gardens) roxburgh's typhonium can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature roxburgh's typhonium can survive?

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

What hardiness zone is roxburgh's typhonium?

Roxburgh's Typhonium is rated USDA 9–11 (may survive mild winters outdoors with mulch; better lifted in colder zones) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can roxburgh's typhonium survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9–11 (may survive mild winters outdoors with mulch; better lifted 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 roxburgh's typhonium 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.