Cold hardiness & minimum temperature

Is Geranium pratense 'Plenum Violaceum' (Geranium pratense 'Plenum Violaceum')cold hardy? Hardiness zone & min temp

Also called Double purple meadow cranesbill, Plenum Violaceum geranium.

More about geranium pratense 'plenum violaceum'

About Geranium pratense 'Plenum Violaceum'

Geranium pratense 'Plenum Violaceum' · also called Double purple meadow cranesbill, Plenum Violaceum geranium · flowering

'Plenum Violaceum' is a fully double meadow cranesbill bearing tightly packed, rosette-like violet-purple flowers in early to midsummer over deeply divided foliage. Being sterile it sets no seed, so it stays put and flowers tidily. Hardy, clump-forming and pollinator-friendly in a modest way, it holds an RHS Award of Garden Merit.

Cold limit: USDA 4-8 · RHS H7 (-29 to 30°C)

What geranium pratense 'plenum violaceum''s hardiness rating actually means

Yes — geranium pratense 'plenum violaceum' is genuinely cold hardy. Rated RHS H7 and USDA 4-8, 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 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 below about −20 °C. Geranium pratense 'Plenum Violaceum' is built for winter — once established it takes hard frost and snow in its stride.

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

Geranium pratense 'Plenum Violaceum' hardiness — frequently asked questions

Is geranium pratense 'plenum violaceum' cold hardy?

Yes — geranium pratense 'plenum violaceum' is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Geranium pratense 'Plenum Violaceum' 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 geranium pratense 'plenum violaceum' can survive?

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

What hardiness zone is geranium pratense 'plenum violaceum'?

Geranium pratense 'Plenum Violaceum' is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can geranium pratense 'plenum violaceum' 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 geranium pratense 'plenum violaceum' 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.