Cold hardiness & minimum temperature

Is Camassia leichtlinii (Camassia leichtlinii)cold hardy? Hardiness zone & min temp

Also called great camas, Leichtlin's camas, blue camas.

More about camassia leichtlinii

About Camassia leichtlinii

Camassia leichtlinii · also called great camas, Leichtlin's camas · flowering

Great camas is a hardy North American bulb that sends up tall spires of star-shaped blue, violet or creamy-white flowers in late spring. Unusually for a bulb, it thrives in moist, even seasonally wet, soils and naturalises beautifully in damp meadows and borders. Plant in autumn, sun to part shade, and leave undisturbed to multiply.

Cold limit: USDA 4-8 · RHS H6 (-29 to 24°C)

What camassia leichtlinii's hardiness rating actually means

Yes — camassia leichtlinii 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. Camassia leichtlinii is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for camassia leichtlinii 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 camassia leichtlinii 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 camassia leichtlinii can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Camassia leichtlinii hardiness — frequently asked questions

Is camassia leichtlinii cold hardy?

Yes — camassia leichtlinii 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. Camassia leichtlinii 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 camassia leichtlinii can survive?

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

What hardiness zone is camassia leichtlinii?

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

Can camassia leichtlinii 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 camassia leichtlinii 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.