Cold hardiness & minimum temperature

Is Kotschy's Crambe (Crambe kotschyana)cold hardy? Hardiness zone & min temp

Also called Kotschy's crambe.

More about kotschy's crambe

About Kotschy's Crambe

Crambe kotschyana · also called Kotschy's crambe · flowering

Crambe kotschyana (sometimes treated taxonomically as Crambe cordifolia subsp. kotschyana) is a large, imposing herbaceous perennial from the mountains of western and central Asia, reaching up to 2.5 m in both height and spread in bloom. Like its close relative C. cordifolia, it produces clouds of small white flowers on dramatically branched stems and features large, lobed basal leaves. It is adaptable to sandy, loamy, or clay soils in full sun or light shade, making it one of the more accommodating large Crambe species. No toxicity has been reported; treat as mildly toxic as a precaution given the absence of ASPCA listing.

Cold limit: USDA 6-9 · RHS H5 (-15°C to 30°C)

What kotschy's crambe's hardiness rating actually means

Yes — kotschy's crambe is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 6-9 — 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 −15 to −10 °C. Kotschy's Crambe is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for kotschy's crambe as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 kotschy's crambe go outside or overwinter — and where?

Plant it out within USDA 6-9 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 kotschy's crambe can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Kotschy's Crambe hardiness — frequently asked questions

Is kotschy's crambe cold hardy?

Yes — kotschy's crambe is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Kotschy's Crambe is hardy across USDA 6-9; 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 kotschy's crambe can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Kotschy's Crambe is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is kotschy's crambe?

Kotschy's Crambe is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can kotschy's crambe survive winter outside?

Plant it out within USDA 6-9 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 kotschy's crambe below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.