Cold hardiness & minimum temperature

Is Mountain crowberry (Empetrum hermaphroditum)cold hardy? Hardiness zone & min temp

Also called Mountain crowberry, Hermaphrodite crowberry, Alpine crowberry.

More about mountain crowberry

About Mountain crowberry

Empetrum hermaphroditum · also called Mountain crowberry, Hermaphrodite crowberry · edible

Mountain crowberry is a hermaphrodite, mat-forming evergreen shrub of boreal forests, alpine heaths, and Arctic tundra. Unlike the dioecious black crowberry, a single plant sets fruit, producing small black berries used in Scandinavian cooking. It is extremely cold-hardy and suited to acidic rock gardens, peat beds, and upland or heathland gardens.

Cold limit: USDA 1-5 · RHS H7 (-40°C to 22°C)

What mountain crowberry's hardiness rating actually means

Yes — mountain crowberry is genuinely cold hardy. Rated RHS H7 and USDA 1-5, 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 1-5 — 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. Mountain crowberry is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for mountain crowberry 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 mountain crowberry go outside or overwinter — and where?

Plant it out within USDA 1-5 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 mountain crowberry can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Mountain crowberry hardiness — frequently asked questions

Is mountain crowberry cold hardy?

Yes — mountain crowberry is genuinely cold hardy. Rated RHS H7 and USDA 1-5, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Mountain crowberry is hardy across USDA 1-5; 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 mountain crowberry can survive?

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

What hardiness zone is mountain crowberry?

Mountain crowberry is rated USDA 1-5 and RHS H7 — Hardy in the severest European continental winters.

Can mountain crowberry survive winter outside?

Plant it out within USDA 1-5 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 mountain crowberry 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.