Cold hardiness & minimum temperature

Is Minnesota Trout Lily (Erythronium propullans)cold hardy? Hardiness zone & min temp

Also called Minnesota Trout Lily, Dwarf Trout Lily, Minnesota Fawnlily.

More about minnesota trout lily

About Minnesota Trout Lily

Erythronium propullans · also called Minnesota Trout Lily, Dwarf Trout Lily · flowering

Erythronium propullans is a critically endangered spring ephemeral endemic to fewer than fourteen populations in Goodhue, Rice, and Steele counties, Minnesota, growing on north-facing slopes above streambeds in dense deciduous woodland. Barely 8–10 cm tall with pale pink flowers the size of a dime, it reproduces almost exclusively via stolons and does not set fertile seed reliably; human attempts to propagate or transplant it have largely failed. It is federally listed as Endangered under the US Endangered Species Act — collecting or disturbing it without a permit is illegal. Erythronium species are not regarded as toxic by the ASPCA; the species is classified mildly-toxic as a precaution given limited specific data.

Cold limit: USDA 3-4 · RHS H7 (-35 to 18°C)

What minnesota trout lily's hardiness rating actually means

Yes — minnesota trout lily is genuinely cold hardy. Rated RHS H7 and USDA 3-4, 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 3-4 — 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. Minnesota Trout Lily is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for minnesota trout lily 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 minnesota trout lily go outside or overwinter — and where?

Plant it out within USDA 3-4 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 minnesota trout lily can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Minnesota Trout Lily hardiness — frequently asked questions

Is minnesota trout lily cold hardy?

Yes — minnesota trout lily is genuinely cold hardy. Rated RHS H7 and USDA 3-4, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Minnesota Trout Lily is hardy across USDA 3-4; 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 minnesota trout lily can survive?

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

What hardiness zone is minnesota trout lily?

Minnesota Trout Lily is rated USDA 3-4 and RHS H7 — Hardy in the severest European continental winters.

Can minnesota trout lily survive winter outside?

Plant it out within USDA 3-4 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 minnesota trout lily 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.