Cold hardiness & minimum temperature

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

Also called yellow cobra lily, Himalayan yellow arisaema.

More about arisaema flavum

About Arisaema flavum

Arisaema flavum · also called yellow cobra lily, Himalayan yellow arisaema · flowering

Arisaema flavum, the yellow cobra lily, is a tuberous Himalayan woodlander grown for its hooded yellow spathes in early summer. It thrives in cool, dappled shade and humus-rich, moisture-retentive but free-draining soil. The tuber goes fully dormant after leaf die-back, needing dry winter rest. Hardy and elegant, it suits shaded borders and woodland gardens.

Cold limit: USDA 5-9 (hardy outdoors with winter mulch) · RHS H5 (13-24°C)

Watch for — Tuber rot in dormancy: Excess winter wet is the main killer. Keep the dormant tuber dry and ensure sharp drainage; lift and store in barely-moist medium in very wet climates.

What arisaema flavum's hardiness rating actually means

Yes — arisaema flavum is genuinely cold hardy. Rated RHS H5 and USDA 5-9 (hardy outdoors with winter mulch), 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 5-9 (hardy outdoors with winter mulch) — 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 flavum is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for arisaema flavum 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 flavum go outside or overwinter — and where?

Plant it out within USDA 5-9 (hardy outdoors with winter mulch) 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 flavum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Arisaema flavum hardiness — frequently asked questions

Is arisaema flavum cold hardy?

Yes — arisaema flavum is genuinely cold hardy. Rated RHS H5 and USDA 5-9 (hardy outdoors with winter mulch), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Arisaema flavum is hardy across USDA 5-9 (hardy outdoors with winter mulch); 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 flavum can survive?

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

What hardiness zone is arisaema flavum?

Arisaema flavum is rated USDA 5-9 (hardy outdoors with winter mulch) and RHS H5 — Hardy in most of the UK and in cold winters.

Can arisaema flavum survive winter outside?

Plant it out within USDA 5-9 (hardy outdoors with winter mulch) 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 flavum 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.