Cold hardiness & minimum temperature

Is Lungwort 'Mrs Moon' (Pulmonaria saccharata)cold hardy? Hardiness zone & min temp

Also called Mrs Moon Lungwort, Bethlehem Sage, Jerusalem Cowslip.

More about lungwort 'mrs moon'

About Lungwort 'Mrs Moon'

Pulmonaria saccharata · also called Mrs Moon Lungwort, Bethlehem Sage · flowering

Lungwort 'Mrs Moon' is a classic spring-flowering shade perennial with heavily silver-spotted, semi-evergreen leaves and funnel-shaped flowers that open pink and age to blue-violet. An excellent ground cover for shaded and woodland borders. Prefers moist, humus-rich soil. Pet-safe according to ASPCA.

Cold limit: USDA 3-8 · RHS H7 (-25-22°C)

What lungwort 'mrs moon''s hardiness rating actually means

Yes — lungwort 'mrs moon' 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 'Mrs Moon' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for lungwort 'mrs moon' 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 'mrs moon' 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 'mrs moon' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Lungwort 'Mrs Moon' hardiness — frequently asked questions

Is lungwort 'mrs moon' cold hardy?

Yes — lungwort 'mrs moon' 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 'Mrs Moon' 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 'mrs moon' can survive?

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

What hardiness zone is lungwort 'mrs moon'?

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

Can lungwort 'mrs moon' 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 'mrs moon' 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.