Cold hardiness & minimum temperature

Is Wormwood (Artemisia absinthium)cold hardy? Hardiness zone & min temp

Also called absinthe wormwood, common wormwood.

About Wormwood

Artemisia absinthium · also called absinthe wormwood, common wormwood · herb

Wormwood is a silvery-leaved Eurasian perennial historically used to flavour absinthe and as an ornamental for grey-foliage borders. Toxic to pets and people in concentrated doses (thujone); decorative use only — do not consume.

Artemisia absinthium is a silver-leaved perennial in the Asteraceae native to North Africa and temperate Eurasia, now naturalized across Canada and the northern US, where it is treated as a noxious weed in some states.

A vigorous, deer- and rabbit-resistant clump that can spread and self-sow; cut back hard in spring to keep it shapely and prevent it from sprawling and shading allelopathy-sensitive neighbors.

Cold limit: USDA 4-9 · RHS H6 (15-26°C)

Watch for — Crown rot in wet winters: Plant in sharp drainage.

Sources: plants.ces.ncsu.edu, montana.edu, kingcounty.gov

What wormwood's hardiness rating actually means

Yes — wormwood 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. Wormwood is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for wormwood 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 wormwood 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 wormwood can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Wormwood hardiness — frequently asked questions

Is wormwood cold hardy?

Yes — wormwood 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. Wormwood 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 wormwood can survive?

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

What hardiness zone is wormwood?

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

Can wormwood 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 wormwood 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.