Cold hardiness & minimum temperature

Is Pink mountain heather (Phyllodoce empetriformis)cold hardy? Hardiness zone & min temp

Also called Pink mountain heather, Red mountain heather, Empetrum-leaved phyllodoce.

More about pink mountain heather

About Pink mountain heather

Phyllodoce empetriformis · also called Pink mountain heather, Red mountain heather · flowering

Pink mountain heather is a spreading alpine subshrub native to western North America, from Alaska to California and the Rocky Mountains, bearing abundant rose-pink to magenta urn-shaped flowers in late spring. Its dense, needle-like evergreen foliage forms attractive mats suited to acidic cool rock gardens, and it is among the most ornamental of the mountain heathers.

Cold limit: USDA 3-7 · RHS H7 (−25 to 18°C)

Watch for — Sparse flowering: Insufficient winter cold or excessive shade can reduce flower production. Ensure at least some direct sunlight and allow plants to experience natural cold winters. In very mild regions, flowering is often poor regardless of other conditions.

What pink mountain heather's hardiness rating actually means

Yes — pink mountain heather is genuinely cold hardy. Rated RHS H7 and USDA 3-7, 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 3-7 — 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. Pink mountain heather is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for pink 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 pink mountain heather go outside or overwinter — and where?

Plant it out within USDA 3-7 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 pink 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.

Pink mountain heather hardiness — frequently asked questions

Is pink mountain heather cold hardy?

Yes — pink mountain heather is genuinely cold hardy. Rated RHS H7 and USDA 3-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Pink mountain heather is hardy across USDA 3-7; 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 pink mountain heather can survive?

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

What hardiness zone is pink mountain heather?

Pink mountain heather is rated USDA 3-7 and RHS H7 — Hardy in the severest European continental winters.

Can pink mountain heather survive winter outside?

Plant it out within USDA 3-7 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 pink 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.