Cold hardiness & minimum temperature

Is Kidney Vetch (Anthyllis vulneraria)cold hardy? Hardiness zone & min temp

Also called Kidney Vetch, Lady's Fingers, Woundwort.

More about kidney vetch

About Kidney Vetch

Anthyllis vulneraria · also called Kidney Vetch, Lady's Fingers · flowering

Anthyllis vulneraria is a low-growing perennial or biennial legume native to calcareous grasslands, cliffs, and coastal dunes across Europe, North Africa, and western Asia. It bears dense, woolly heads of yellow, orange, or red flowers from June to September and fixes atmospheric nitrogen through root nodule bacteria. The most important care fact is excellent drainage on infertile, alkaline soil: rich or waterlogged conditions cause rapid decline. The plant is not known to be toxic to pets.

Cold limit: USDA 4-9 · RHS H6 (-20 to 28°C)

What kidney vetch's hardiness rating actually means

Yes — kidney vetch is genuinely cold hardy. Rated RHS H6 and USDA 4-9, 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 4-9 — 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. Kidney Vetch is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for kidney vetch 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 kidney vetch go outside or overwinter — and where?

Plant it out within USDA 4-9 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 kidney vetch can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Kidney Vetch hardiness — frequently asked questions

Is kidney vetch cold hardy?

Yes — kidney vetch is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Kidney Vetch is hardy across USDA 4-9; 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 kidney vetch can survive?

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

What hardiness zone is kidney vetch?

Kidney Vetch is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can kidney vetch survive winter outside?

Plant it out within USDA 4-9 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 kidney vetch 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.