Cold hardiness & minimum temperature

Is Starry Solomon's Seal (Maianthemum stellatum)cold hardy? Hardiness zone & min temp

Also called Starry Solomon's seal, Starry false Solomon's seal, Star-flowered lily of the valley.

More about starry solomon's seal

About Starry Solomon's Seal

Maianthemum stellatum · also called Starry Solomon's seal, Starry false Solomon's seal · flowering

Maianthemum stellatum is a native North American woodland perennial found from Alaska south to California and east across Canada and the northern United States, typically colonising moist, shaded slopes and stream margins. It produces unbranched arching stems with lance-shaped leaves and terminal clusters of small, white, star-shaped flowers in late spring, followed by striking striped berries that ripen to deep red or purplish-black. The single most important care requirement is consistently moist, humus-rich, acidic soil in part to full shade; it spreads slowly by rhizome and is best left undisturbed once established. The berries contain steroidal saponins and the plant is not listed on the ASPCA database as non-toxic — treat as mildly toxic to cats and dogs.

Cold limit: USDA 3-7 · RHS H7 (-35 to 25°C)

What starry solomon's seal's hardiness rating actually means

Yes — starry solomon's seal is genuinely cold hardy. Rated RHS H7 and USDA 3-7, 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 3-7 — 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 below about −20 °C. Starry Solomon's Seal is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for starry solomon's seal 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 starry solomon's seal 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 starry solomon's seal can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Starry Solomon's Seal hardiness — frequently asked questions

Is starry solomon's seal cold hardy?

Yes — starry solomon's seal is genuinely cold hardy. Rated RHS H7 and USDA 3-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Starry Solomon's Seal 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 starry solomon's seal can survive?

Minimum survivable temperature is roughly below about −20 °C. Starry Solomon's Seal is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is starry solomon's seal?

Starry Solomon's Seal is rated USDA 3-7 and RHS H7 — Hardy in the severest European continental winters.

Can starry solomon's seal 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 starry solomon's seal 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.