Cold hardiness & minimum temperature

Is Geranium psilostemon (Geranium psilostemon)cold hardy? Hardiness zone & min temp

Also called Armenian cranesbill.

More about geranium psilostemon

About Geranium psilostemon

Geranium psilostemon · also called Armenian cranesbill · flowering

Geranium psilostemon, Armenian cranesbill, is a large, statuesque hardy geranium making a bold clump of deeply lobed leaves topped in summer by vivid magenta flowers with striking black centres and veins. It needs space, supports itself fairly well, and brings electric colour to mixed borders. Foliage frequently turns red and orange in autumn.

Cold limit: USDA 5-8 · RHS H7 (-29 to 30°C)

What geranium psilostemon's hardiness rating actually means

Yes — geranium psilostemon is genuinely cold hardy. Rated RHS H7 and USDA 5-8, 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 5-8 — 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 below about −20 °C. Geranium psilostemon is built for winter — once established it takes hard frost and snow in its stride.

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

Geranium psilostemon hardiness — frequently asked questions

Is geranium psilostemon cold hardy?

Yes — geranium psilostemon is genuinely cold hardy. Rated RHS H7 and USDA 5-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Geranium psilostemon 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 geranium psilostemon can survive?

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

What hardiness zone is geranium psilostemon?

Geranium psilostemon is rated USDA 5-8 and RHS H7 — Hardy in the severest European continental winters.

Can geranium psilostemon 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 geranium psilostemon 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.