Cold hardiness & minimum temperature

Is Autumn Daffodil (Sternbergia lutea)cold hardy? Hardiness zone & min temp

Also called Autumn daffodil, Winter daffodil, Lily-of-the-field, Yellow autumn crocus.

More about autumn daffodil

About Autumn Daffodil

Sternbergia lutea · also called Autumn daffodil, Winter daffodil · flowering

Sternbergia lutea is a small bulbous perennial native to the Mediterranean region and the Middle East, producing brilliant golden-yellow, goblet-shaped flowers in autumn directly alongside or just before the narrow, glossy strap leaves emerge. It thrives in full sun with excellent drainage, alkaline soil, and a warm, dry summer baking period — conditions that replicate its native rocky hillside habitat. Plant the bulbs deeply in a sheltered south-facing border or raised bed in late summer for best results. All parts of this plant contain Amaryllidaceae alkaloids and are toxic to pets.

Cold limit: USDA 7-9 · RHS H5 (-15–35°C)

What autumn daffodil's hardiness rating actually means

Yes — autumn daffodil is genuinely cold hardy. Rated RHS H5 and USDA 7-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 7-9 — 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 −15 to −10 °C. Autumn Daffodil is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for autumn daffodil as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 autumn daffodil go outside or overwinter — and where?

Plant it out within USDA 7-9 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 autumn daffodil can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Frost protection for borderline autumn daffodil

Autumn Daffodil is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes.
Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness.
Shelter new growth from late spring frosts with fleece if a hard night is forecast.

Autumn Daffodil hardiness — frequently asked questions

Is autumn daffodil cold hardy?

Yes — autumn daffodil is genuinely cold hardy. Rated RHS H5 and USDA 7-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Autumn Daffodil is hardy across USDA 7-9; 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 autumn daffodil can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Autumn Daffodil is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is autumn daffodil?

Autumn Daffodil is rated USDA 7-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can autumn daffodil survive winter outside?

Plant it out within USDA 7-9 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.

How do I protect autumn daffodil from frost?

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes. Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness. Shelter new growth from late spring frosts with fleece if a hard night is forecast.