Cold hardiness & minimum temperature

Is Glory of the Snow (Chionodoxa forbesii)cold hardy? Hardiness zone & min temp

Also called Glory of the snow, Forbes' glory of the snow, Star of the snow.

More about glory of the snow

About Glory of the Snow

Chionodoxa forbesii · also called Glory of the snow, Forbes' glory of the snow · flowering

Glory of the snow is a small, early-spring-flowering bulb native to the mountains of western Turkey, producing clusters of upward-facing, sky-blue flowers with a contrasting white eye on stems 10–15 cm tall. It naturalises readily in short grass, gravel gardens, and beneath deciduous trees, spreading both by seed and offsets to form dense drifts over time. The single most important care rule is to leave the foliage to die back completely before mowing or removing it, as the leaves feed the bulb for next year. The bulbs can cause mild gastrointestinal upset if ingested and should be kept out of reach of pets.

Cold limit: USDA 3-8 · RHS H6 (-20 to 20°C)

Watch for — Squirrel and rodent damage: Small corms are attractive to squirrels and mice, especially in autumn after planting. Cover freshly planted beds with wire mesh pinned to the soil surface, removed once shoots emerge in late winter.

What glory of the snow's hardiness rating actually means

Yes — glory of the snow is genuinely cold hardy. Rated RHS H6 and USDA 3-8, 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 3-8 — 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. Glory of the Snow is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for glory of the snow 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 glory of the snow go outside or overwinter — and where?

Plant it out within USDA 3-8 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 glory of the snow can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Glory of the Snow hardiness — frequently asked questions

Is glory of the snow cold hardy?

Yes — glory of the snow is genuinely cold hardy. Rated RHS H6 and USDA 3-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Glory of the Snow is hardy across USDA 3-8; 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 glory of the snow can survive?

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

What hardiness zone is glory of the snow?

Glory of the Snow is rated USDA 3-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can glory of the snow survive winter outside?

Plant it out within USDA 3-8 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 glory of the snow 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.