Cold hardiness & minimum temperature

Is Thornless Evergreen Blackberry (Rubus laciniatus 'Thornless Evergreen')cold hardy? Hardiness zone & min temp

Also called thornless evergreen blackberry, cutleaf blackberry.

More about thornless evergreen blackberry

About Thornless Evergreen Blackberry

Rubus laciniatus 'Thornless Evergreen' · also called thornless evergreen blackberry, cutleaf blackberry · edible

'Thornless Evergreen' is a vigorous, semi-evergreen blackberry with deeply cut leaves and long, thornless canes that crop heavily in late summer. Productive and easy to harvest, it yields firm, flavourful berries that freeze well, holds its foliage in mild winters, and trains neatly along wires or fences for the home grower.

Cold limit: USDA 6-9 · RHS H5 (-15 to 30°C)

What thornless evergreen blackberry's hardiness rating actually means

Yes — thornless evergreen blackberry 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. Thornless Evergreen Blackberry is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for thornless evergreen blackberry 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 thornless evergreen blackberry 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 thornless evergreen blackberry can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Thornless Evergreen Blackberry hardiness — frequently asked questions

Is thornless evergreen blackberry cold hardy?

Yes — thornless evergreen blackberry 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. Thornless Evergreen Blackberry 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 thornless evergreen blackberry can survive?

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

What hardiness zone is thornless evergreen blackberry?

Thornless Evergreen Blackberry is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can thornless evergreen blackberry 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 thornless evergreen blackberry 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.