Cold hardiness & minimum temperature

Is Small-Flowered Cranesbill (Geranium pusillum)cold hardy? Hardiness zone & min temp

Also called Small-Flowered Cranesbill, Small Geranium.

More about small-flowered cranesbill

About Small-Flowered Cranesbill

Geranium pusillum · also called Small-Flowered Cranesbill, Small Geranium · flowering

Geranium pusillum is a slender, softly hairy annual native to Eurasia and now naturalised widely in North America, typically found on arable field margins, roadsides and disturbed ground. It bears very small pale lilac-pink flowers from June to September and is an undemanding plant that thrives in lean, freely draining soils. The most important care point is that it dislikes rich, moist soils — excessive fertility produces leafy growth at the expense of its delicate flowers. 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 5-8 · RHS H6 (-15 to 25°C)

What small-flowered cranesbill's hardiness rating actually means

Yes — small-flowered cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 5-8, 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 5-8 — 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. Small-Flowered Cranesbill is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for small-flowered 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 small-flowered cranesbill go outside or overwinter — and where?

Plant it out within USDA 5-8 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 small-flowered cranesbill can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Small-Flowered Cranesbill hardiness — frequently asked questions

Is small-flowered cranesbill cold hardy?

Yes — small-flowered cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 5-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Small-Flowered Cranesbill is hardy across USDA 5-8; 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 small-flowered cranesbill can survive?

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

What hardiness zone is small-flowered cranesbill?

Small-Flowered Cranesbill is rated USDA 5-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can small-flowered cranesbill survive winter outside?

Plant it out within USDA 5-8 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 small-flowered 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.