Cold hardiness & minimum temperature

Is Arisaema jacquemontii (Arisaema jacquemontii)cold hardy? Hardiness zone & min temp

Also called Jacquemont's cobra lily, high-altitude arisaema.

More about arisaema jacquemontii

About Arisaema jacquemontii

Arisaema jacquemontii · also called Jacquemont's cobra lily, high-altitude arisaema · flowering

Arisaema jacquemontii is a hardy Himalayan cobra lily growing from a tuber, with a single divided leaf and an elegant green-and-white striped hooded spathe in late spring. Unlike its tropical relatives it tolerates cold, thriving in cool, humus-rich, well-drained woodland soil in part shade. A choice, deciduous tuberous perennial for shaded borders and woodland gardens in temperate climates.

Cold limit: USDA 6-9 · RHS H5 (5-25°C)

Watch for — Tuber rot: Cold, waterlogged winter soil rots the dormant tuber. Plant on a well-drained site or raised bed and improve heavy ground with grit and leaf mould.

What arisaema jacquemontii's hardiness rating actually means

Yes — arisaema jacquemontii is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 6-9 — 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 −15 to −10 °C. Arisaema jacquemontii is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for arisaema jacquemontii as it gets too cold:

It tolerates winter lows to about −15 to −10 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can arisaema jacquemontii go outside or overwinter — and where?

Plant it out within USDA 6-9 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

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 arisaema jacquemontii can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Arisaema jacquemontii hardiness — frequently asked questions

Is arisaema jacquemontii cold hardy?

Yes — arisaema jacquemontii is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Arisaema jacquemontii is hardy across USDA 6-9; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature arisaema jacquemontii can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Arisaema jacquemontii is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is arisaema jacquemontii?

Arisaema jacquemontii is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can arisaema jacquemontii survive winter outside?

Plant it out within USDA 6-9 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to arisaema jacquemontii below its minimum temperature?

It tolerates winter lows to about −15 to −10 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.