Cold hardiness & minimum temperature

Is Long-Stalked Cranesbill (Geranium columbinum)cold hardy? Hardiness zone & min temp

Also called Long-Stalked Cranesbill, Longstalk Cranesbill.

More about long-stalked cranesbill

About Long-Stalked Cranesbill

Geranium columbinum · also called Long-Stalked Cranesbill, Longstalk Cranesbill · flowering

Geranium columbinum is a slender, wiry-stemmed annual native to the UK and much of Europe, western Asia and North Africa, favouring dry calcareous grassland, hedgebanks, cliff slopes and field margins from lowland up to around 1,200 m. Its deeply cut, finely divided leaves and small pink to purple flowers appear from April to September, carried on distinctively long, slender pedicels that give the species its name. It requires well-drained, preferably calcareous soils in a warm, sunny position and dislikes wet or shaded conditions. True cranesbill Geranium species are not listed as toxic to pets by the ASPCA, and this species is considered non-toxic to cats and dogs.

Cold limit: USDA 5-9 · RHS H6 (-15 to 25°C)

What long-stalked cranesbill's hardiness rating actually means

Yes — long-stalked cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 5-9, 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 5-9 — 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. Long-Stalked Cranesbill is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for long-stalked cranesbill 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 long-stalked cranesbill go outside or overwinter — and where?

Plant it out within USDA 5-9 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 long-stalked cranesbill can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Long-Stalked Cranesbill hardiness — frequently asked questions

Is long-stalked cranesbill cold hardy?

Yes — long-stalked cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Long-Stalked Cranesbill is hardy across USDA 5-9; 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 long-stalked cranesbill can survive?

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

What hardiness zone is long-stalked cranesbill?

Long-Stalked Cranesbill is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can long-stalked cranesbill survive winter outside?

Plant it out within USDA 5-9 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 long-stalked cranesbill 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.