Cold hardiness & minimum temperature

Is Showy Cranesbill (Geranium × magnificum)cold hardy? Hardiness zone & min temp

Also called Showy Cranesbill, Purple Cranesbill, Magnificent Hardy Geranium.

More about showy cranesbill

About Showy Cranesbill

Geranium × magnificum · also called Showy Cranesbill, Purple Cranesbill · flowering

Geranium × magnificum is a sterile hybrid (G. ibericum × G. platypetalum) of garden origin, producing some of the largest and most intensely coloured flowers in the genus — deep violet-blue with darker veining, up to 5 cm across, in early summer. It forms vigorous, shaggy clumps of deeply divided leaves that colour well in autumn. Because the plant sets no seed, deadheading is unnecessary, but cutting the whole plant back hard after flowering refreshes foliage for the rest of the season. True Geranium species are non-toxic to cats and dogs according to ASPCA guidance.

Cold limit: USDA 4-8 · RHS H6 (-20 to 28°C)

What showy cranesbill's hardiness rating actually means

Yes — showy cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 4-8, 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 4-8 — 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. Showy Cranesbill is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for showy 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 showy cranesbill go outside or overwinter — and where?

Plant it out within USDA 4-8 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 showy cranesbill can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Showy Cranesbill hardiness — frequently asked questions

Is showy cranesbill cold hardy?

Yes — showy cranesbill is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Showy Cranesbill is hardy across USDA 4-8; 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 showy cranesbill can survive?

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

What hardiness zone is showy cranesbill?

Showy Cranesbill is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can showy cranesbill survive winter outside?

Plant it out within USDA 4-8 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 showy 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.