Cold hardiness & minimum temperature

Is Geranium phaeum 'Album' (Geranium phaeum 'Album')cold hardy? Hardiness zone & min temp

Also called White dusky cranesbill, Album mourning widow.

More about geranium phaeum 'album'

About Geranium phaeum 'Album'

Geranium phaeum 'Album' · also called White dusky cranesbill, Album mourning widow · flowering

Geranium phaeum 'Album' is the pure-white form of the dusky cranesbill, lighting up shade with small, reflexed white flowers on slender stems above fresh green leaves in late spring and early summer. The white blooms glow in dim, woodland conditions where darker forms can disappear. It is a tough, shade- and dry-shade-tolerant perennial that naturalises gently beneath trees and shrubs.

Cold limit: USDA 4-8 (outdoor hardy perennial) · RHS H7 (-25 to 25°C)

What geranium phaeum 'album''s hardiness rating actually means

Yes — geranium phaeum 'album' is genuinely cold hardy. Rated RHS H7 and USDA 4-8 (outdoor hardy perennial), 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 (outdoor hardy perennial) — 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. Geranium phaeum 'Album' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for geranium phaeum 'album' 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 geranium phaeum 'album' go outside or overwinter — and where?

Plant it out within USDA 4-8 (outdoor hardy perennial) 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 geranium phaeum 'album' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Geranium phaeum 'Album' hardiness — frequently asked questions

Is geranium phaeum 'album' cold hardy?

Yes — geranium phaeum 'album' is genuinely cold hardy. Rated RHS H7 and USDA 4-8 (outdoor hardy perennial), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Geranium phaeum 'Album' is hardy across USDA 4-8 (outdoor hardy perennial); 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 geranium phaeum 'album' can survive?

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

What hardiness zone is geranium phaeum 'album'?

Geranium phaeum 'Album' is rated USDA 4-8 (outdoor hardy perennial) and RHS H7 — Hardy in the severest European continental winters.

Can geranium phaeum 'album' survive winter outside?

Plant it out within USDA 4-8 (outdoor hardy perennial) 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 geranium phaeum 'album' 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.