Cold hardiness & minimum temperature

Is Dragon Arum (Dracunculus vulgaris)cold hardy? Hardiness zone & min temp

Also called dragon arum, dragon lily, stink lily, voodoo lily.

More about dragon arum

About Dragon Arum

Dracunculus vulgaris · also called dragon arum, dragon lily · flowering

Dracunculus vulgaris is a dramatic Mediterranean tuberous perennial famous for its huge deep-maroon spathe and long black spadix that reek of carrion for a day or two to lure pollinating flies. Its dragon-like mottled stems and divided leaves rise in spring; it loves sun, sharp drainage and a dry summer dormancy.

Cold limit: USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8) · RHS H4 (15-27°C)

Watch for — Tuber rot in wet winters: Cold, soggy soil during dormancy rots the tuber. Plant in sharp drainage on a slope or raised bed and keep dormant tubers dry.

What dragon arum's hardiness rating actually means

Yes — dragon arum is genuinely cold hardy. Rated RHS H4 and USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8) — 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 −10 to −5 °C. Dragon Arum is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for dragon arum as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 dragon arum go outside or overwinter — and where?

Plant it out within USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8) 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 dragon arum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Dragon Arum hardiness — frequently asked questions

Is dragon arum cold hardy?

Yes — dragon arum is genuinely cold hardy. Rated RHS H4 and USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Dragon Arum is hardy across USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8); 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 dragon arum can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Dragon Arum is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is dragon arum?

Dragon Arum is rated USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8) and RHS H4 — Hardy in an average winter across much of the temperate world.

Can dragon arum survive winter outside?

Plant it out within USDA 5-8 (mulch the tuber in colder gardens; reliably hardy in 6-8) 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 dragon arum below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.