Cold hardiness & minimum temperature

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

Also called blue Atlas cedar, blue cedar.

More about blue atlas cedar

About Blue Atlas Cedar

Cedrus atlantica 'Glauca' · also called blue Atlas cedar, blue cedar · flowering

Blue Atlas cedar is a striking large evergreen conifer prized for its silvery powder-blue needles held in tufts on stiff, ascending branches. Native to North Africa's Atlas Mountains, it loves full sun and sharp drainage, becoming drought-tolerant once established. Slow to moderate in youth, it matures into a broad, majestic specimen tree.

Cold limit: USDA 6-9 · RHS H6 (-20 to 32°C)

Watch for — Tip blight / needle browning: Browning shoot tips can follow fungal infection or cold winds; prune out affected growth and avoid overhead watering.

What blue atlas cedar's hardiness rating actually means

Yes — blue atlas cedar is genuinely cold hardy. Rated RHS H6 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. 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 −20 to −15 °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 −20 to −15 °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 H6 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 H6 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 −20 to −15 °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 H6 — Hardy throughout the UK and northern Europe.

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 −20 to −15 °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.