Cold hardiness & minimum temperature

Is Lungwort (Pulmonaria officinalis)cold hardy? Hardiness zone & min temp

Also called Lungwort, Common Lungwort, Jerusalem Cowslip, Spotted Dog.

More about lungwort

About Lungwort

Pulmonaria officinalis · also called Lungwort, Common Lungwort · flowering

Pulmonaria officinalis is a shade-loving, semi-evergreen rhizomatous perennial native to damp woodland and scrub across central and southern Europe. It is valued as an early-spring groundcover, producing clusters of funnel-shaped flowers that open pink and mature to blue-violet, followed by large, white-spotted leaves that remain attractive all summer. The most important care principle is consistent shade and moisture — hot sun and dry soil cause the leaves to scorch and collapse by midsummer. Lungwort contains pyrrolizidine alkaloids and saponins and should be considered toxic to cats and dogs.

Cold limit: USDA 3-8 · RHS H7 (-25 °C to 20 °C)

Watch for — Vine weevil grubs: C-shaped white grubs feeding on rhizomes cause plants to wilt suddenly; apply nematode biological control (Steinernema kraussei) in late summer to early autumn when soil temperature is above 5 °C.

What lungwort's hardiness rating actually means

Yes — lungwort is genuinely cold hardy. Rated RHS H7 and USDA 3-8, 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 3-8 — 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. Lungwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for lungwort 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 lungwort go outside or overwinter — and where?

Plant it out within USDA 3-8 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 lungwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Lungwort hardiness — frequently asked questions

Is lungwort cold hardy?

Yes — lungwort is genuinely cold hardy. Rated RHS H7 and USDA 3-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Lungwort is hardy across USDA 3-8; 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 lungwort can survive?

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

What hardiness zone is lungwort?

Lungwort is rated USDA 3-8 and RHS H7 — Hardy in the severest European continental winters.

Can lungwort survive winter outside?

Plant it out within USDA 3-8 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 lungwort 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.