Cold hardiness & minimum temperature

Is Norfolk Island pine (Araucaria heterophylla)cold hardy? Hardiness zone & min temp

Also called Norfolk pine, house pine, star pine.

About Norfolk Island pine

Araucaria heterophylla · also called Norfolk pine, house pine · houseplant

Norfolk Island pine is a tender conifer-relative from Norfolk Island in the South Pacific, sold widely as a small "indoor Christmas tree". It is not winter-hardy and needs bright light and even humidity to stay full and symmetrical. Pet-safe by ASPCA standards.

Araucaria heterophylla is endemic to Norfolk Island and tiny Philip Island in the South Pacific, roughly 1,400 km east of Australia, where a frost-free subtropical climate with about 1,350 mm of evenly spread annual rainfall and little seasonal variation lets it reach over 50 m as a forest tree.

Tender to frost (about USDA zone 10-11), so it is grown as a houseplant in most of the US and UK; tropical Norfolk pines prefer roughly 65-70F and around 50% humidity, and it has earned the RHS Award of Garden Merit as a conservatory/house conifer.

Cold limit: USDA 10-11 (indoor-only in most US homes) · RHS H1c (16-24°C)

Sources: rhs.org.uk, plants.ces.ncsu.edu, libguides.nybg.org, en.wikipedia.org

What norfolk island pine's hardiness rating actually means

Norfolk Island pine 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 10-11 (indoor-only in most US homes) — 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). Norfolk Island pine has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for norfolk island pine 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 norfolk island pine 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 norfolk island pine can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Norfolk Island pine hardiness — frequently asked questions

Is norfolk island pine cold hardy?

Norfolk Island pine 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. Norfolk Island pine can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor-only in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature norfolk island pine can survive?

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

What hardiness zone is norfolk island pine?

Norfolk Island pine is rated USDA 10-11 (indoor-only in most US homes) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can norfolk island pine 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 norfolk island pine 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.