Cold hardiness & minimum temperature

Is Aleutian Mountain Heath (Phyllodoce aleutica)cold hardy? Hardiness zone & min temp

Also called Aleutian Mountain Heath, Aleutian Mountain Heather, Yellow Mountain Heath.

More about aleutian mountain heath

About Aleutian Mountain Heath

Phyllodoce aleutica · also called Aleutian Mountain Heath, Aleutian Mountain Heather · flowering

Phyllodoce aleutica is a dwarf evergreen heath-like shrub native to alpine and subalpine zones of Alaska, the Aleutian Islands, and Japan, forming low mats of needle-like leaves in exposed, rocky tundra and mountain meadows. It thrives in cool, moist, acidic conditions and is intolerant of summer heat or waterlogged roots. The single most important care fact is that it requires a reliably acidic, humus-rich, free-draining but consistently moist soil — drying out even briefly can be fatal. Toxicity to cats and dogs has not been confirmed by ASPCA; as a member of Ericaceae with limited toxicological data, treat as mildly toxic and keep pets away.

Cold limit: USDA 4-7 · RHS H7 (-30°C to 18°C)

What aleutian mountain heath's hardiness rating actually means

Yes — aleutian mountain heath is genuinely cold hardy. Rated RHS H7 and USDA 4-7, 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 4-7 — 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 Heath is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for aleutian mountain heath 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 heath go outside or overwinter — and where?

Plant it out within USDA 4-7 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 heath 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 Heath hardiness — frequently asked questions

Is aleutian mountain heath cold hardy?

Yes — aleutian mountain heath is genuinely cold hardy. Rated RHS H7 and USDA 4-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Aleutian Mountain Heath is hardy across USDA 4-7; 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 heath can survive?

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

What hardiness zone is aleutian mountain heath?

Aleutian Mountain Heath is rated USDA 4-7 and RHS H7 — Hardy in the severest European continental winters.

Can aleutian mountain heath survive winter outside?

Plant it out within USDA 4-7 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 heath 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.