Cold hardiness & minimum temperature

Is Caucasian Rock Cress (Arabis caucasica)cold hardy? Hardiness zone & min temp

Also called Caucasian Rock Cress, Wall Cress, Mountain Cress.

More about caucasian rock cress

About Caucasian Rock Cress

Arabis caucasica · also called Caucasian Rock Cress, Wall Cress · flowering

One of the most widely grown spring rock garden plants, Arabis caucasica produces dense mats of grey-green foliage smothered in fragrant white (or pink, in cultivars) flowers from late winter through spring. Vigorous, easy to grow, and highly frost-hardy. Excellent for dry walls, rock gardens, and border fronts. Cut back hard after flowering to maintain tidiness.

Cold limit: USDA 3–7 · RHS H7 (-25 to 28°C)

Watch for — Root rot in wet conditions: Heavy clay soils or prolonged winter waterlogging causes collar and root rot. Improve soil drainage before planting and avoid mulching directly against the crown. Wall crevice planting largely eliminates this risk.

What caucasian rock cress's hardiness rating actually means

Yes — caucasian rock cress is genuinely cold hardy. Rated RHS H7 and USDA 3–7, 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 3–7 — 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. Caucasian Rock Cress is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for caucasian rock cress 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 caucasian rock cress go outside or overwinter — and where?

Plant it out within USDA 3–7 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 caucasian rock cress can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Caucasian Rock Cress hardiness — frequently asked questions

Is caucasian rock cress cold hardy?

Yes — caucasian rock cress is genuinely cold hardy. Rated RHS H7 and USDA 3–7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Caucasian Rock Cress is hardy across USDA 3–7; 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 caucasian rock cress can survive?

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

What hardiness zone is caucasian rock cress?

Caucasian Rock Cress is rated USDA 3–7 and RHS H7 — Hardy in the severest European continental winters.

Can caucasian rock cress survive winter outside?

Plant it out within USDA 3–7 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 caucasian rock cress 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.