Cold hardiness & minimum temperature

Is Blue Atlas Cedar (Cedrus atlantica 'Glauca')cold hardy? Hardiness zone & min temp

Also called Blue Atlas Cedar, Glauca Blue Cedar, Glaucous Atlas Cedar.

More about blue atlas cedar

About Blue Atlas Cedar

Cedrus atlantica 'Glauca' · also called Blue Atlas Cedar, Glauca Blue Cedar · flowering

Blue Atlas Cedar is a striking large evergreen conifer prized for its powder-blue needles and imposing pyramidal to broadly spreading habit. Native to the Atlas Mountains of Morocco and Algeria, it is drought-tolerant once established and thrives in full sun on well-drained soils. A long-lived, low-maintenance specimen tree for large gardens.

Cold limit: USDA 6-9 · RHS H5 (-20 to 35°C)

Watch for — Wind scorch and snow damage: Young trees with their wide horizontal branches are vulnerable to snow loading and strong winds, which can split or break branches. Stake firmly for the first 3 years; shake off heavy snow accumulation. Siting out of prevailing cold winds reduces scorch risk.

What blue atlas cedar's hardiness rating actually means

Yes — blue atlas cedar is genuinely cold hardy. Rated RHS H5 and USDA 6-9, 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 6-9 — 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 −15 to −10 °C. Blue Atlas Cedar is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for blue atlas cedar 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 blue atlas cedar go outside or overwinter — and where?

Plant it out within USDA 6-9 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 blue atlas cedar can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Blue Atlas Cedar hardiness — frequently asked questions

Is blue atlas cedar cold hardy?

Yes — blue atlas cedar is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Blue Atlas Cedar is hardy across USDA 6-9; 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 blue atlas cedar can survive?

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

What hardiness zone is blue atlas cedar?

Blue Atlas Cedar is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can blue atlas cedar survive winter outside?

Plant it out within USDA 6-9 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 blue atlas cedar 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.