Cold hardiness & minimum temperature

Is Mugwort (Artemisia vulgaris)cold hardy? Hardiness zone & min temp

Also called mugwort, common wormwood, wild wormwood.

More about mugwort

About Mugwort

Artemisia vulgaris · also called mugwort, common wormwood · herb

Mugwort is a vigorous, aromatic perennial herb grown for its silvery, deeply lobed foliage and historic culinary and medicinal uses. It thrives in full sun and poor, dry soil, spreading aggressively by rhizomes and seed. Once established it needs almost no care, tolerating drought, neglect and exposed sites, but it readily becomes invasive if left unchecked.

Cold limit: USDA 3-9 (cold-hardy perennial) · RHS H7 (-1 to 30°C)

What mugwort's hardiness rating actually means

Yes — mugwort is genuinely cold hardy. Rated RHS H7 and USDA 3-9 (cold-hardy perennial), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 3-9 (cold-hardy perennial) — 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 below about −20 °C. Mugwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for mugwort as it gets too cold:

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

Plant it out within USDA 3-9 (cold-hardy perennial) 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 mugwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Mugwort hardiness — frequently asked questions

Is mugwort cold hardy?

Yes — mugwort is genuinely cold hardy. Rated RHS H7 and USDA 3-9 (cold-hardy perennial), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Mugwort is hardy across USDA 3-9 (cold-hardy perennial); 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 mugwort can survive?

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

What hardiness zone is mugwort?

Mugwort is rated USDA 3-9 (cold-hardy perennial) and RHS H7 — Hardy in the severest European continental winters.

Can mugwort survive winter outside?

Plant it out within USDA 3-9 (cold-hardy perennial) 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 mugwort below its minimum temperature?

It tolerates winter lows to about −20 °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.