Cold hardiness & minimum temperature

Is Yellow Barrenwort (Epimedium x versicolor 'Sulphureum')cold hardy? Hardiness zone & min temp

Also called Yellow Barrenwort, Sulphur Barrenwort, Bishop's Hat.

More about yellow barrenwort

About Yellow Barrenwort

Epimedium x versicolor 'Sulphureum' · also called Yellow Barrenwort, Sulphur Barrenwort · flowering

'Sulphureum' is among the most reliable and widely grown Epimediums, producing cheerful pale-yellow spurred flowers in mid-spring above semi-evergreen, heart-shaped foliage with attractive bronze-red winter tints. Exceptionally tough and drought-tolerant once established, it is a top choice for dry shade beneath trees and large shrubs. RHS Award of Garden Merit holder.

Cold limit: USDA 5-9 · RHS H7 (-25°C to 30°C)

Watch for — Flowers hidden by old evergreen foliage: The most common mistake is failing to cut back the previous year's semi-evergreen leaves before flowering. Clip all foliage to the ground in late winter (February in the UK) to fully display the spring flower display.

What yellow barrenwort's hardiness rating actually means

Yes — yellow barrenwort is genuinely cold hardy. Rated RHS H7 and USDA 5-9, 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 5-9 — 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 below about −20 °C. Yellow Barrenwort is built for winter — once established it takes hard frost and snow in its stride.

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

Plant it out within USDA 5-9 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 yellow barrenwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Yellow Barrenwort hardiness — frequently asked questions

Is yellow barrenwort cold hardy?

Yes — yellow barrenwort is genuinely cold hardy. Rated RHS H7 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Yellow Barrenwort is hardy across USDA 5-9; 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 yellow barrenwort can survive?

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

What hardiness zone is yellow barrenwort?

Yellow Barrenwort is rated USDA 5-9 and RHS H7 — Hardy in the severest European continental winters.

Can yellow barrenwort survive winter outside?

Plant it out within USDA 5-9 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 yellow 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.