Cold hardiness & minimum temperature

Is Hairy Woodrush (Luzula pilosa)cold hardy? Hardiness zone & min temp

Also called Hairy woodrush, Hairy wood-rush.

More about hairy woodrush

About Hairy Woodrush

Luzula pilosa · also called Hairy woodrush, Hairy wood-rush · flowering

Luzula pilosa is a delicate, native European woodland plant found across the UK and temperate Eurasia, distinguished by its grass-like leaves covered in long, silky white hairs and its small chestnut-brown flower clusters borne on wiry stems in spring. It is an ideal low-growing, shade-tolerant ground cover for naturalistic and woodland gardens. The most important care fact is that it self-seeds readily, making it useful for naturalising but requiring control in formal plantings. Not listed as toxic; considered pet-safe.

Cold limit: USDA 4-8 · RHS H7 (-20°C to 22°C)

What hairy woodrush's hardiness rating actually means

Yes — hairy woodrush 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. Hairy Woodrush is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hairy woodrush 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 hairy woodrush 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 hairy woodrush can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Hairy Woodrush hardiness — frequently asked questions

Is hairy woodrush cold hardy?

Yes — hairy woodrush 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. Hairy Woodrush 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 hairy woodrush can survive?

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

What hardiness zone is hairy woodrush?

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

Can hairy woodrush 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 hairy woodrush 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.