Cold hardiness & minimum temperature

Is Aleutian mountain heather (Phyllodoce aleutica)cold hardy? Hardiness zone & min temp

Also called Aleutian mountain heather, Yellow mountain heather, Cream mountain heather.

More about aleutian mountain heather

About Aleutian mountain heather

Phyllodoce aleutica · also called Aleutian mountain heather, Yellow mountain heather · flowering

Aleutian mountain heather is a distinctive low-growing ericaceous subshrub native to the Aleutian Islands, Alaska, Japan, and Kamchatka, bearing creamy-yellow to pale greenish-white urn-shaped flowers — unusual within the pink-purple Phyllodoce genus. It forms compact, heath-like mats and demands cool, moist, acidic conditions, making it a specialist plant for cold-climate rock gardens.

Cold limit: USDA 3-6 · RHS H7 (−25 to 15°C)

What aleutian mountain heather's hardiness rating actually means

Yes — aleutian mountain heather is genuinely cold hardy. Rated RHS H7 and USDA 3-6, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 3-6 — 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 below about −20 °C. Aleutian mountain heather is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for aleutian mountain heather as it gets too cold:

It tolerates winter lows to about −20 °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 aleutian mountain heather go outside or overwinter — and where?

Plant it out within USDA 3-6 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 aleutian mountain heather can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Aleutian mountain heather hardiness — frequently asked questions

Is aleutian mountain heather cold hardy?

Yes — aleutian mountain heather is genuinely cold hardy. Rated RHS H7 and USDA 3-6, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Aleutian mountain heather is hardy across USDA 3-6; 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 aleutian mountain heather can survive?

Minimum survivable temperature is roughly below about −20 °C. Aleutian mountain heather is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is aleutian mountain heather?

Aleutian mountain heather is rated USDA 3-6 and RHS H7 — Hardy in the severest European continental winters.

Can aleutian mountain heather survive winter outside?

Plant it out within USDA 3-6 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 aleutian mountain heather below its minimum temperature?

It tolerates winter lows to about −20 °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.