Cold hardiness & minimum temperature

Is King Billy Pine (Athrotaxis selaginoides)cold hardy? Hardiness zone & min temp

Also called King Billy pine, king William pine.

More about king billy pine

About King Billy Pine

Athrotaxis selaginoides · also called King Billy pine, king William pine · flowering

King Billy pine is a slow-growing, long-lived evergreen conifer endemic to Tasmania's cool, wet mountain forests. It forms a narrow conical crown of dense, awl-shaped, spreading needles on reddish, fibrous bark. Demanding cool, moist, acidic, free-draining soil, constant humidity, and shelter, it is best suited to cool-temperate gardens and resents heat and drought.

Cold limit: USDA 8-9 · RHS H5 (-10 to 22°C)

What king billy pine's hardiness rating actually means

Yes — king billy pine is genuinely cold hardy. Rated RHS H5 and USDA 8-9, 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 8-9 — 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. King Billy Pine is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for king billy pine 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 king billy pine go outside or overwinter — and where?

Plant it out within USDA 8-9 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 king billy pine can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

King Billy Pine hardiness — frequently asked questions

Is king billy pine cold hardy?

Yes — king billy pine is genuinely cold hardy. Rated RHS H5 and USDA 8-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. King Billy Pine is hardy across USDA 8-9; 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 king billy pine can survive?

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

What hardiness zone is king billy pine?

King Billy Pine is rated USDA 8-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can king billy pine survive winter outside?

Plant it out within USDA 8-9 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 king billy pine 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.