Cold hardiness & minimum temperature

Is Cantabrian Draba (Draba dedeana)cold hardy? Hardiness zone & min temp

Also called Cantabrian Draba, Dedean's Draba, Spanish Whitlow Grass.

More about cantabrian draba

About Cantabrian Draba

Draba dedeana · also called Cantabrian Draba, Dedean's Draba · flowering

Draba dedeana is a diminutive cushion-forming perennial from limestone rock faces and crevices in the Cantabrian Mountains and Pyrenees of Spain, where it grows at subalpine to alpine elevations. It forms tiny, hard, shiny-green rosettes of toothed leaves and bears disproportionately large, pure white flowers — often the first rockery Draba to bloom in late winter or very early spring. Gritty, well-drained soil and full sun are essential; it is an excellent candidate for a trough or alpine house where winter rainfall can be managed. Toxicity data are absent from the ASPCA database; classified as mildly-toxic as a precaution.

Cold limit: USDA 5-9 · RHS H5 (-20 to 20°C)

Watch for — Crown rot in wet winters: The principal risk in the UK; even well-drained soil can become too wet during prolonged rainy winters — cover with a pane of glass or move to an alpine house from October to March.

What cantabrian draba's hardiness rating actually means

Yes — cantabrian draba is genuinely cold hardy. Rated RHS H5 and USDA 5-9, 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 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 −15 to −10 °C. Cantabrian Draba is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for cantabrian draba 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 cantabrian draba 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 cantabrian draba can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Cantabrian Draba hardiness — frequently asked questions

Is cantabrian draba cold hardy?

Yes — cantabrian draba is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Cantabrian Draba 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 cantabrian draba can survive?

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

What hardiness zone is cantabrian draba?

Cantabrian Draba is rated USDA 5-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can cantabrian draba 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 cantabrian draba 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.