Cold hardiness & minimum temperature

Is Hedge Woundwort (Stachys sylvatica)cold hardy? Hardiness zone & min temp

Also called Hedge Woundwort, Whitespot.

More about hedge woundwort

About Hedge Woundwort

Stachys sylvatica · also called Hedge Woundwort, Whitespot · flowering

Hedge woundwort is a robust herbaceous perennial native to woodland edges, hedgerows, and shaded banks across Europe and western Asia. It thrives in moist, humus-rich soils in dappled to full shade, making it ideal for naturalising under trees or in wild gardens. The most important care fact is that it spreads readily by rhizomes and self-seeding, so containment is needed in formal beds. It is not listed on the ASPCA toxic plant database, but crushed foliage produces a strongly unpleasant odour that typically deters pets from ingesting it; classify as mildly-toxic out of caution.

Cold limit: USDA 4-8 · RHS H7 (-20 to 25°C)

What hedge woundwort's hardiness rating actually means

Yes — hedge woundwort is genuinely cold hardy. Rated RHS H7 and USDA 4-8, 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 4-8 — 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 below about −20 °C. Hedge Woundwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hedge woundwort 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 hedge woundwort go outside or overwinter — and where?

Plant it out within USDA 4-8 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 hedge woundwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Hedge Woundwort hardiness — frequently asked questions

Is hedge woundwort cold hardy?

Yes — hedge woundwort is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Hedge Woundwort is hardy across USDA 4-8; 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 hedge woundwort can survive?

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

What hardiness zone is hedge woundwort?

Hedge Woundwort is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can hedge woundwort survive winter outside?

Plant it out within USDA 4-8 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 hedge woundwort 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.