Cold hardiness & minimum temperature

Is Lace Fern (Cheilanthes gracillima)cold hardy? Hardiness zone & min temp

Also called Lace Lip Fern, Graceful Lip Fern.

More about lace fern

About Lace Fern

Cheilanthes gracillima · also called Lace Lip Fern, Graceful Lip Fern · houseplant

Lace Fern is a delicate-looking but surprisingly tough native North American fern with finely divided, lacy fronds and dark wiry stems. Despite its dainty appearance, it grows on dry, rocky outcrops in the western USA and tolerates drought well once established. Pteridaceae family ferns are generally considered non-toxic to pets.

Cold limit: USDA 4-8 · RHS H5 (5-25°C)

What lace fern's hardiness rating actually means

Yes — lace fern is genuinely cold hardy. Rated RHS H5 and USDA 4-8, 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 4-8 — 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 −15 to −10 °C. Lace Fern is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for lace fern 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 lace fern go outside or overwinter — and where?

Plant it out within USDA 4-8 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 lace fern can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Lace Fern hardiness — frequently asked questions

Is lace fern cold hardy?

Yes — lace fern is genuinely cold hardy. Rated RHS H5 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Lace Fern is hardy across USDA 4-8; 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 lace fern can survive?

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

What hardiness zone is lace fern?

Lace Fern is rated USDA 4-8 and RHS H5 — Hardy in most of the UK and in cold winters.

Can lace fern survive winter outside?

Plant it out within USDA 4-8 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 lace fern below its minimum temperature?

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.