Cold hardiness & minimum temperature

Is Great Wood Rush (Luzula sylvatica)cold hardy? Hardiness zone & min temp

Also called Great Wood Rush, Greater Wood Rush, Wood Rush.

More about great wood rush

About Great Wood Rush

Luzula sylvatica · also called Great Wood Rush, Greater Wood Rush · flowering

A robust, shade-loving rush forming wide evergreen tufts of broad, grass-like leaves with fine white marginal hairs. Grows 30–80 cm tall and spreads slowly by stolons, making it one of the best ground-cover plants for dry shade. Not listed as toxic by the ASPCA; considered pet-safe.

Cold limit: USDA 5-9 · RHS H7 (−20–30°C)

What great wood rush's hardiness rating actually means

Yes — great wood rush is genuinely cold hardy. Rated RHS H7 and USDA 5-9, 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 5-9 — 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 below about −20 °C. Great Wood Rush is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for great wood rush 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 great wood rush go outside or overwinter — and where?

Plant it out within USDA 5-9 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 great wood rush can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Great Wood Rush hardiness — frequently asked questions

Is great wood rush cold hardy?

Yes — great wood rush is genuinely cold hardy. Rated RHS H7 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Great Wood Rush is hardy across USDA 5-9; 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 great wood rush can survive?

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

What hardiness zone is great wood rush?

Great Wood Rush is rated USDA 5-9 and RHS H7 — Hardy in the severest European continental winters.

Can great wood rush survive winter outside?

Plant it out within USDA 5-9 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 great wood rush 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.