Cold hardiness & minimum temperature

Is Besom heath (Erica scoparia)cold hardy? Hardiness zone & min temp

Also called Besom heath, Green heather, Broom heath.

More about besom heath

About Besom heath

Erica scoparia · also called Besom heath, Green heather · flowering

A tall, upright western Mediterranean heath grown chiefly for its airy, needle-like dark green foliage and architectural form. Small, greenish-brown bell-shaped flowers appear in late spring and early summer, releasing pollen in clouds. Fully hardy (RHS H5), it tolerates exposed sites and poor, acidic, sharply drained soils. Historically used to make brooms and is the source of briar pipe root burls in some regions.

Cold limit: USDA 6–9 · RHS H5 (-15 to 35°C)

What besom heath's hardiness rating actually means

Yes — besom heath is genuinely cold hardy. Rated RHS H5 and USDA 6–9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 6–9 — 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 about −15 to −10 °C. Besom heath is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for besom heath as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 besom heath go outside or overwinter — and where?

Plant it out within USDA 6–9 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 besom heath can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Besom heath hardiness — frequently asked questions

Is besom heath cold hardy?

Yes — besom heath is genuinely cold hardy. Rated RHS H5 and USDA 6–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Besom heath is hardy across USDA 6–9; 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 besom heath can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Besom heath is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is besom heath?

Besom heath is rated USDA 6–9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can besom heath survive winter outside?

Plant it out within USDA 6–9 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 besom heath below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.