Cold hardiness & minimum temperature

Is Maire's fescue (Festuca mairei)cold hardy? Hardiness zone & min temp

Also called Maire's fescue, Atlas fescue, Moroccan fescue.

More about maire's fescue

About Maire's fescue

Festuca mairei · also called Maire's fescue, Atlas fescue · flowering

Maire's fescue is a large, architectural evergreen grass from the Atlas Mountains of Morocco. It forms impressive fountain-like mounds of fine, silver-green to khaki-green foliage and is exceptionally drought-tolerant once established. Longer-lived and more heat-tolerant than most fescues, it suits dry gardens, gravel borders, and Mediterranean-style landscaping in zones 4–10.

Cold limit: USDA 4-10 · RHS H5 (-20 to 38°C)

Watch for — Crown rot in poorly drained soils: Despite being more robust than smaller fescues, it will rot if the crown sits in poorly drained, waterlogged soil over winter; amend heavy clay with grit or plant on a slight slope to encourage water run-off.

What maire's fescue's hardiness rating actually means

Yes — maire's fescue is genuinely cold hardy. Rated RHS H5 and USDA 4-10, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 4-10 — 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 −15 to −10 °C. Maire's fescue is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for maire's fescue as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 maire's fescue go outside or overwinter — and where?

Plant it out within USDA 4-10 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 maire's fescue can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Maire's fescue hardiness — frequently asked questions

Is maire's fescue cold hardy?

Yes — maire's fescue is genuinely cold hardy. Rated RHS H5 and USDA 4-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Maire's fescue is hardy across USDA 4-10; 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 maire's fescue can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Maire's fescue is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is maire's fescue?

Maire's fescue is rated USDA 4-10 and RHS H5 — Hardy in most of the UK and in cold winters.

Can maire's fescue survive winter outside?

Plant it out within USDA 4-10 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 maire's fescue below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.