Cold hardiness & minimum temperature

Is Blue Star Fern (Phlebodium aureum)cold hardy? Hardiness zone & min temp

Also called Blue star fern, Golden polypody, Cabbage palm fern, Gold-foot fern, Hare's-foot fern.

More about blue star fern

About Blue Star Fern

Phlebodium aureum · also called Blue star fern, Golden polypody · tropical

The blue star fern is an epiphytic tropical fern grown for its arching, wavy, blue-green fronds that rise from a furry, creeping rhizome. Its one defining care need is steady moisture without sogginess: keep the loose, organic mix lightly damp at all times, but never let the rhizome sit waterlogged, which quickly causes rot.

Cold limit: USDA 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere) · RHS H1b (min 10-15°C; can go outside in summer, needs warmth and frost-free protection in winter) (16-24°C)

What blue star fern's hardiness rating actually means

Blue Star Fern is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere) — 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 10 °C (sustained cold below this is damaging). Blue Star Fern has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for blue star fern as it gets too cold:

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can blue star fern go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 blue star fern can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Blue Star Fern hardiness — frequently asked questions

Is blue star fern cold hardy?

Blue Star Fern is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Blue Star Fern can only live outside year-round in genuinely frost-free climates (roughly USDA 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature blue star fern can survive?

What hardiness zone is blue star fern?

Blue Star Fern is rated USDA 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can blue star fern survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to blue star fern below its minimum temperature?

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.