Cold hardiness & minimum temperature

Is Cretan Climbing Fern (Lygodium microphyllum)cold hardy? Hardiness zone & min temp

Also called Old World Climbing Fern, Small-leaved Climbing Fern.

More about cretan climbing fern

About Cretan Climbing Fern

Lygodium microphyllum · also called Old World Climbing Fern, Small-leaved Climbing Fern · houseplant

Lygodium microphyllum is a true climbing fern whose fronds behave like vines, twining indefinitely via an ever-extending rachis up supports. Native to Africa, Asia, and Australia, it is a serious invasive weed in Florida wetlands, so it should never be planted outdoors in warm regions. Grown indoors on a trellis it wants bright indirect light, warmth, humidity, and steady moisture.

Cold limit: USDA 9-11; do NOT plant outdoors where it can escape — it is an aggressive invasive · RHS H1c (18-28°C)

What cretan climbing fern's hardiness rating actually means

Cretan Climbing 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 9-11; do NOT plant outdoors where it can escape — it is an aggressive invasive — 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 5 °C (and never frost). Cretan Climbing Fern has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for cretan climbing fern as it gets too cold:

Below about about 5 °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 cretan climbing fern go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 cretan climbing fern can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Cretan Climbing Fern hardiness — frequently asked questions

Is cretan climbing fern cold hardy?

Cretan Climbing 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. Cretan Climbing Fern can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11; do NOT plant outdoors where it can escape — it is an aggressive invasive); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature cretan climbing fern can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Cretan Climbing Fern has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is cretan climbing fern?

Cretan Climbing Fern is rated USDA 9-11; do NOT plant outdoors where it can escape — it is an aggressive invasive and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can cretan climbing fern survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 cretan climbing fern below its minimum temperature?

Below about about 5 °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.