Cold hardiness & minimum temperature

Is Blue Cloud Cranesbill (Geranium 'Blue Cloud')cold hardy? Hardiness zone & min temp

Also called Blue Cloud Cranesbill, Blue Cloud Geranium.

More about blue cloud cranesbill

About Blue Cloud Cranesbill

Geranium 'Blue Cloud' · also called Blue Cloud Cranesbill, Blue Cloud Geranium · flowering

Geranium 'Blue Cloud' is a large, spreading hybrid likely raised as a seedling of 'Nimbus' at Axletree Nursery, Scotland, producing very finely dissected foliage on a sprawling plant that can reach 90 cm tall and 170 cm wide. Pale sky-blue flowers with fine dark purple veins appear from late spring through summer. This is one of the largest hardy cranesbills and may need support or space at the back of a border; it received the RHS Award of Garden Merit in 2004. ASPCA's 'Geranium' toxic listing refers to Pelargonium; true cranesbills are not confirmed non-toxic by ASPCA, so treat with caution around pets.

Cold limit: USDA 5-9 · RHS H7 (-20°C to 30°C)

What blue cloud cranesbill's hardiness rating actually means

Yes — blue cloud cranesbill is genuinely cold hardy. Rated RHS H7 and USDA 5-9, 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 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 below about −20 °C. Blue Cloud Cranesbill is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for blue cloud cranesbill 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 blue cloud 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 blue cloud cranesbill can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Blue Cloud Cranesbill hardiness — frequently asked questions

Is blue cloud cranesbill cold hardy?

Yes — blue cloud cranesbill is genuinely cold hardy. Rated RHS H7 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Blue Cloud 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 blue cloud cranesbill can survive?

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

What hardiness zone is blue cloud cranesbill?

Blue Cloud Cranesbill is rated USDA 5-9 and RHS H7 — Hardy in the severest European continental winters.

Can blue cloud 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 blue cloud cranesbill 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.