Cold hardiness & minimum temperature

Is Hoop Pine (Araucaria cunninghamii)cold hardy? Hardiness zone & min temp

Also called hoop pine, colonial pine, Moreton Bay pine.

More about hoop pine

About Hoop Pine

Araucaria cunninghamii · also called hoop pine, colonial pine · flowering

Araucaria cunninghamii, the hoop pine, is a tall Australian rainforest conifer named for the horizontal bark rings ringing its trunk. It carries dark, scale-like needles in tufts at branch tips and a distinctive domed crown. A slow-growing landscape and timber tree in warm climates, young plants make handsome, symmetrical indoor or patio specimens like its Norfolk relative.

Cold limit: USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) · RHS H2 (13-27°C)

Watch for — Brown needle tips: Very dry indoor air or inconsistent watering browns the needle tips. Maintain even moisture and moderate humidity, and keep the plant away from heating vents and drafts.

What hoop pine's hardiness rating actually means

Hoop Pine is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) — 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 1 to 5 °C — tolerates cold but no real frost. Hoop Pine shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for hoop pine as it gets too cold:

Down to roughly about 1 to 5 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can hoop pine go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 hoop pine can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline hoop pine

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

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Hoop Pine hardiness — frequently asked questions

Is hoop pine cold hardy?

Hoop Pine is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) (and sheltered UK gardens) hoop pine can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature hoop pine can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Hoop Pine shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is hoop pine?

Hoop Pine is rated USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can hoop pine survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (frost-tender; indoor or patio plant in cooler regions) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect hoop pine from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.