Cold hardiness & minimum temperature

Is Rose campion (Lychnis coronaria)cold hardy? Hardiness zone & min temp

Also called Rose campion, Dusty miller, Mullein pink.

More about rose campion

About Rose campion

Lychnis coronaria · also called Rose campion, Dusty miller · flowering

A biennial to short-lived perennial with vividly magenta-crimson (or white) flowers held above distinctive silver-white, woolly stems and leaves from early to midsummer. Thrives in full sun in poor, well-drained soil. Extremely drought-tolerant and self-seeds freely. Pet-safe. A classic cottage-garden plant that naturalises with minimal care.

Cold limit: USDA 4-8 · RHS H6 (-20 to 35°C)

Watch for — Root and crown rot: The number-one killer. Wet, poorly draining soil — especially in winter — causes rapid rotting of the woolly crown. Ensure excellent drainage, particularly in clay soils, and avoid mulching directly over the crown.

What rose campion's hardiness rating actually means

Yes — rose campion is genuinely cold hardy. Rated RHS H6 and USDA 4-8, 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 4-8 — 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 about −20 to −15 °C. Rose campion is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for rose campion 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 rose campion 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 rose campion can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Rose campion hardiness — frequently asked questions

Is rose campion cold hardy?

Yes — rose campion is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Rose campion 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 rose campion can survive?

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

What hardiness zone is rose campion?

Rose campion is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can rose campion 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 rose campion 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.