Cold hardiness & minimum temperature

Is Cross-leaved Heath Alba Mollis (Erica tetralix 'Alba Mollis')cold hardy? Hardiness zone & min temp

Also called Cross-leaved Heath, Bog Heather, Cross-leaved Heather.

More about cross-leaved heath alba mollis

About Cross-leaved Heath Alba Mollis

Erica tetralix 'Alba Mollis' · also called Cross-leaved Heath, Bog Heather · flowering

Erica tetralix 'Alba Mollis' is a compact, silver-foliaged form of cross-leaved heath native to boggy moorlands across northern and western Europe. It thrives in consistently moist, acid soil and tolerates wetter conditions than most heaths — do not let it dry out. The silvery-grey leaves and nodding white bell-shaped flowers appear from mid-summer into autumn. This species is not known to be toxic to cats or dogs.

Cold limit: USDA 4-7 · RHS H7 (-20 to 25 °C)

What cross-leaved heath alba mollis's hardiness rating actually means

Yes — cross-leaved heath alba mollis 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. Cross-leaved Heath Alba Mollis is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for cross-leaved heath alba mollis 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 cross-leaved heath alba mollis 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 cross-leaved heath alba mollis can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Cross-leaved Heath Alba Mollis hardiness — frequently asked questions

Is cross-leaved heath alba mollis cold hardy?

Yes — cross-leaved heath alba mollis 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. Cross-leaved Heath Alba Mollis 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 cross-leaved heath alba mollis can survive?

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

What hardiness zone is cross-leaved heath alba mollis?

Cross-leaved Heath Alba Mollis is rated USDA 4-7 and RHS H7 — Hardy in the severest European continental winters.

Can cross-leaved heath alba mollis 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 cross-leaved heath alba mollis 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.