Cold hardiness & minimum temperature

Is Persian Barrenwort (Epimedium pinnatum)cold hardy? Hardiness zone & min temp

Also called Persian Barrenwort, Pinnate Barrenwort.

More about persian barrenwort

About Persian Barrenwort

Epimedium pinnatum · also called Persian Barrenwort, Pinnate Barrenwort · flowering

Persian Barrenwort is a robust, semi-evergreen species from the forests of Iran and the Caucasus, bearing bright yellow flowers with brown spurs in mid-spring. Its bold, pinnate leaves are attractive year-round and develop reddish tints in winter. One of the most drought-tolerant and weed-suppressing Epimediums, excellent for difficult dry shade situations.

Cold limit: USDA 5-9 · RHS H6 (-20°C to 30°C)

Watch for — Winter-damaged foliage: Although semi-evergreen, the large leaves may be damaged by hard frosts in exposed positions. Plants readily re-foliate from rhizomes. Cut back any tatty winter foliage to ground level in late February before new growth emerges.

What persian barrenwort's hardiness rating actually means

Yes — persian barrenwort is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. 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 about −20 to −15 °C. Persian Barrenwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for persian barrenwort as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 persian 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 persian barrenwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Persian Barrenwort hardiness — frequently asked questions

Is persian barrenwort cold hardy?

Yes — persian barrenwort is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Persian 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 persian barrenwort can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Persian Barrenwort is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is persian barrenwort?

Persian Barrenwort is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can persian 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 persian barrenwort below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.