Cold hardiness & minimum temperature

Is Pyrenean Star of Bethlehem (Ornithogalum pyrenaicum)cold hardy? Hardiness zone & min temp

Also called Pyrenean star of Bethlehem, Bath asparagus, Spiked star of Bethlehem, French asparagus.

More about pyrenean star of bethlehem

About Pyrenean Star of Bethlehem

Ornithogalum pyrenaicum · also called Pyrenean star of Bethlehem, Bath asparagus · flowering

Ornithogalum pyrenaicum is a stately spring-to-early-summer bulb native to open woodlands and grasslands across western and central Europe, including Britain, where it is a scarce native plant most famously associated with the woodlands around Bath, Somerset. Its tall, erect spikes of pale greenish-white, starry flowers open from bottom to top and are valued as a long-lasting cut flower. Historically the young flower spikes were gathered and eaten as 'Bath asparagus', though this is no longer recommended given its protected status in the wild; cultivated plants are best enjoyed in the border or cutting garden with minimal interference after planting. All Ornithogalum species are toxic to pets.

Cold limit: USDA 5-9 · RHS H6 (-20 to 22°C)

What pyrenean star of bethlehem's hardiness rating actually means

Yes — pyrenean star of bethlehem is genuinely cold hardy. Rated RHS H6 and USDA 5-9, 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 5-9 — 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. Pyrenean Star of Bethlehem is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for pyrenean star of bethlehem 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 pyrenean star of bethlehem go outside or overwinter — and where?

Plant it out within USDA 5-9 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 pyrenean star of bethlehem can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Pyrenean Star of Bethlehem hardiness — frequently asked questions

Is pyrenean star of bethlehem cold hardy?

Yes — pyrenean star of bethlehem is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Pyrenean Star of Bethlehem is hardy across USDA 5-9; 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 pyrenean star of bethlehem can survive?

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

What hardiness zone is pyrenean star of bethlehem?

Pyrenean Star of Bethlehem is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can pyrenean star of bethlehem survive winter outside?

Plant it out within USDA 5-9 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 pyrenean star of bethlehem 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.