Cold hardiness & minimum temperature

Is Many-haired Draba (Draba polytricha)cold hardy? Hardiness zone & min temp

Also called Many-haired Draba, Many-haired Whitlowgrass.

More about many-haired draba

About Many-haired Draba

Draba polytricha · also called Many-haired Draba, Many-haired Whitlowgrass · flowering

Many-haired Draba is a specialist cushion alpine from volcanic and rocky habitats in Turkey and Armenia, characterised by leaves densely clothed in star-shaped (stellate) hairs giving the plant a silver-grey appearance. Bright yellow flowers emerge in early spring on very short stems. It is highly regarded by alpine enthusiasts and best grown in an alpine house or well-protected trough.

Cold limit: USDA 4–8 · RHS H7 (-20–20°C)

Watch for — Cushion die-back after stress: The plant can collapse suddenly after a wet period, heavy frost, or root disturbance. Act quickly: cut away dead portions, dust with sulphur, and replant healthy sections in fresh, dry gritty compost.

What many-haired draba's hardiness rating actually means

Yes — many-haired draba is genuinely cold hardy. Rated RHS H7 and USDA 4–8, 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 4–8 — 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. Many-haired Draba is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for many-haired draba 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 many-haired draba go outside or overwinter — and where?

Plant it out within USDA 4–8 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 many-haired draba can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Many-haired Draba hardiness — frequently asked questions

Is many-haired draba cold hardy?

Yes — many-haired draba is genuinely cold hardy. Rated RHS H7 and USDA 4–8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Many-haired Draba is hardy across USDA 4–8; 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 many-haired draba can survive?

Minimum survivable temperature is roughly below about −20 °C. Many-haired Draba is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is many-haired draba?

Many-haired Draba is rated USDA 4–8 and RHS H7 — Hardy in the severest European continental winters.

Can many-haired draba survive winter outside?

Plant it out within USDA 4–8 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 many-haired draba 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.