Cold hardiness & minimum temperature

Is Red Barrenwort (Epimedium x rubrum)cold hardy? Hardiness zone & min temp

Also called Red Barrenwort, Red Bishop's Hat, Red Fairy Wings.

More about red barrenwort

About Red Barrenwort

Epimedium x rubrum · also called Red Barrenwort, Red Bishop's Hat · flowering

Red Barrenwort is a vigorous hybrid Epimedium bearing small but prolific crimson-and-yellow spurred flowers in spring above heart-shaped leaves. New spring foliage emerges with striking red-bronze marbling; autumn colour is equally ornamental. Exceptionally drought-tolerant once established, thriving in dry shade beneath large trees. Deer and rabbit resistant.

Cold limit: USDA 4-8 · RHS H7 (-25°C to 30°C)

Watch for — Old foliage masking spring flowers: The semi-evergreen foliage persists through winter and can obscure emerging flowers. Cut all growth to within a few centimetres of the ground in late winter before buds break — typically February in the UK, March in colder US zones.

What red barrenwort's hardiness rating actually means

Yes — red barrenwort is genuinely cold hardy. Rated RHS H7 and USDA 4-8, 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 4-8 — 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. Red Barrenwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for red barrenwort 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 red barrenwort go outside or overwinter — and where?

Plant it out within USDA 4-8 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 red barrenwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Red Barrenwort hardiness — frequently asked questions

Is red barrenwort cold hardy?

Yes — red barrenwort is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Red Barrenwort is hardy across USDA 4-8; 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 red barrenwort can survive?

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

What hardiness zone is red barrenwort?

Red Barrenwort is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can red barrenwort survive winter outside?

Plant it out within USDA 4-8 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 red barrenwort 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.