Cold hardiness & minimum temperature

Is Round-leaved Wintergreen (Pyrola rotundifolia)cold hardy? Hardiness zone & min temp

Also called Round-leaved Wintergreen, Round-leafed Pyrola.

More about round-leaved wintergreen

About Round-leaved Wintergreen

Pyrola rotundifolia · also called Round-leaved Wintergreen, Round-leafed Pyrola · flowering

A delicate, evergreen woodland perennial native to Europe and northern Asia, bearing racemes of fragrant, nodding white flowers in summer. It thrives in cool, moist, humus-rich soil under dappled shade and is notoriously difficult to establish — requiring a mycorrhizal relationship and precise soil conditions to grow well.

Cold limit: USDA 4-8 · RHS H7 (-25 to 20°C)

What round-leaved wintergreen's hardiness rating actually means

Yes — round-leaved wintergreen is genuinely cold hardy. Rated RHS H7 and USDA 4-8, 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 4-8 — 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. Round-leaved Wintergreen is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for round-leaved wintergreen 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 round-leaved wintergreen go outside or overwinter — and where?

Plant it out within USDA 4-8 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 round-leaved wintergreen can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Round-leaved Wintergreen hardiness — frequently asked questions

Is round-leaved wintergreen cold hardy?

Yes — round-leaved wintergreen is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Round-leaved Wintergreen is hardy across USDA 4-8; 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 round-leaved wintergreen can survive?

Minimum survivable temperature is roughly below about −20 °C. Round-leaved Wintergreen is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is round-leaved wintergreen?

Round-leaved Wintergreen is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can round-leaved wintergreen survive winter outside?

Plant it out within USDA 4-8 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 round-leaved wintergreen 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.