Cold hardiness & minimum temperature

Is Prostrate Blue Noble Fir (Abies procera 'Glauca Prostrata')cold hardy? Hardiness zone & min temp

Also called Prostrate Blue Noble Fir, Blue Noble Fir, Glauca Prostrata Fir.

More about prostrate blue noble fir

About Prostrate Blue Noble Fir

Abies procera 'Glauca Prostrata' · also called Prostrate Blue Noble Fir, Blue Noble Fir · flowering

Abies procera 'Glauca Prostrata' is a low-growing, spreading cultivar of Noble Fir native to the Pacific Northwest of North America, prized for its striking silver-blue needles. It hugs the ground or cascades over walls, rarely exceeding 0.5 m in height but spreading to 1.5–2 m wide over many years. The most important care fact is ensuring excellent drainage — soggy roots cause rapid needle drop and root rot. Abies species are not listed as toxic to cats or dogs by the ASPCA, though needle ingestion may cause mild gastrointestinal irritation.

Cold limit: USDA 5-7 · RHS H6 (-20°C to 25°C)

Watch for — Adelgids (Adelges spp.): Woolly adelgids form white, waxy tufts at the base of needles and on new shoots, causing needle yellowing and premature drop. Treat with a horticultural oil spray in late winter before bud break, or a systemic neonicotinoid applied to the soil.

What prostrate blue noble fir's hardiness rating actually means

Yes — prostrate blue noble fir is genuinely cold hardy. Rated RHS H6 and USDA 5-7, 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 5-7 — 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. Prostrate Blue Noble Fir is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for prostrate blue noble fir 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 prostrate blue noble fir go outside or overwinter — and where?

Plant it out within USDA 5-7 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 prostrate blue noble fir can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Prostrate Blue Noble Fir hardiness — frequently asked questions

Is prostrate blue noble fir cold hardy?

Yes — prostrate blue noble fir is genuinely cold hardy. Rated RHS H6 and USDA 5-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Prostrate Blue Noble Fir is hardy across USDA 5-7; 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 prostrate blue noble fir can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Prostrate Blue Noble Fir is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is prostrate blue noble fir?

Prostrate Blue Noble Fir is rated USDA 5-7 and RHS H6 — Hardy throughout the UK and northern Europe.

Can prostrate blue noble fir survive winter outside?

Plant it out within USDA 5-7 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 prostrate blue noble fir 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.