Cold hardiness & minimum temperature

Is Common Camas (Camassia quamash)cold hardy? Hardiness zone & min temp

Also called Common camas, Quamash, Small camas, Wild hyacinth.

More about common camas

About Common Camas

Camassia quamash · also called Common camas, Quamash · edible

Common camas is a bulbous perennial native to moist meadows and prairies of western North America, where it was a critical food staple for many Indigenous peoples including the Nez Perce. It thrives in moisture-retentive, fertile soil in full sun to light shade and produces spikes of violet-blue star-shaped flowers in late spring. The single most important care fact is never to allow the foliage to be removed before it dies back naturally, as the bulb needs those weeks to store energy for the following year. The bulbs of common camas are considered non-toxic to humans and pets when correctly identified, but must not be confused with death camas (Anticlea elegans syn. Zigadenus venenosus), a highly toxic look-alike — always source plants from reputable nurseries.

Cold limit: USDA 3-7 · RHS H4 (-35 to 25°C)

What common camas's hardiness rating actually means

Yes — common camas is genuinely cold hardy. Rated RHS H4 and USDA 3-7, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 3-7 — 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 −10 to −5 °C. Common Camas is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for common camas as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 common camas go outside or overwinter — and where?

Plant it out within USDA 3-7 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 common camas can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Common Camas hardiness — frequently asked questions

Is common camas cold hardy?

Yes — common camas is genuinely cold hardy. Rated RHS H4 and USDA 3-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Common Camas is hardy across USDA 3-7; 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 common camas can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Common Camas is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is common camas?

Common Camas is rated USDA 3-7 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can common camas survive winter outside?

Plant it out within USDA 3-7 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 common camas below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.