Cold hardiness & minimum temperature

Is Borealis Honeyberry (Lonicera caerulea 'Borealis')cold hardy? Hardiness zone & min temp

Also called Borealis honeyberry, haskap Borealis.

More about borealis honeyberry

About Borealis Honeyberry

Lonicera caerulea 'Borealis' · also called Borealis honeyberry, haskap Borealis · edible

'Borealis' is a University of Saskatchewan haskap (blue honeysuckle) prized for large, sweet-tart blue berries that ripen very early, before strawberries. Exceptionally cold-hardy and easy to grow, it needs a compatible partner such as 'Honey Bee' or 'Aurora' for cross-pollination. The soft, elongated berries are excellent fresh, frozen or in preserves.

Cold limit: USDA 2-7 · RHS H7 (-45 to 30°C)

What borealis honeyberry's hardiness rating actually means

Yes — borealis honeyberry is genuinely cold hardy. Rated RHS H7 and USDA 2-7, 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 2-7 — 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 below about −20 °C. Borealis Honeyberry is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for borealis honeyberry 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 borealis honeyberry go outside or overwinter — and where?

Plant it out within USDA 2-7 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 borealis honeyberry can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Borealis Honeyberry hardiness — frequently asked questions

Is borealis honeyberry cold hardy?

Yes — borealis honeyberry is genuinely cold hardy. Rated RHS H7 and USDA 2-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Borealis Honeyberry is hardy across USDA 2-7; 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 borealis honeyberry can survive?

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

What hardiness zone is borealis honeyberry?

Borealis Honeyberry is rated USDA 2-7 and RHS H7 — Hardy in the severest European continental winters.

Can borealis honeyberry survive winter outside?

Plant it out within USDA 2-7 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 borealis honeyberry 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.