Cold hardiness & minimum temperature

Is Green Dragon (Arisaema dracontium)cold hardy? Hardiness zone & min temp

Also called Green Dragon, Dragon Root, Dragon Arum.

More about green dragon

About Green Dragon

Arisaema dracontium · also called Green Dragon, Dragon Root · flowering

Green Dragon is a native North American woodland aroid distinguished by its single leaf divided into 7–15 leaflets and an unusually long spadix protruding dramatically from the green spathe. It naturalises readily in moist, shaded borders and floodplains, tolerating harder winters than most Arisaema. Clusters of bright red berries follow in summer.

Cold limit: USDA 4-9 · RHS H6 (-29°C to 25°C (dormant corm); 10–25°C growing)

Watch for — Premature summer dormancy: Green Dragon goes dormant naturally in late summer, but drought or excessive heat accelerates this. Ensure consistent soil moisture through summer; a thick mulch helps retain moisture and moderate soil temperature.

What green dragon's hardiness rating actually means

Yes — green dragon is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 4-9 — 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 −20 to −15 °C. Green Dragon is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for green dragon as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 green dragon go outside or overwinter — and where?

Plant it out within USDA 4-9 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 green dragon can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Green Dragon hardiness — frequently asked questions

Is green dragon cold hardy?

Yes — green dragon is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Green Dragon is hardy across USDA 4-9; 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 green dragon can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Green Dragon is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is green dragon?

Green Dragon is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can green dragon survive winter outside?

Plant it out within USDA 4-9 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 green dragon below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.