Cold hardiness & minimum temperature

Is Rosemary (Rosmarinus officinalis)cold hardy? Hardiness zone & min temp

Also called Rosemary, Common Rosemary.

More about rosemary

About Rosemary

Rosmarinus officinalis · also called Rosemary, Common Rosemary · herb

An iconic evergreen Mediterranean shrub with aromatic, needle-like leaves used widely in culinary and ornamental settings. Thrives in full sun and well-drained, lean soil; highly drought-tolerant once established. Hardy in USDA zones 8–11, with cold-hardy cultivars surviving in zone 6–7. Produces pale blue flowers in spring and sporadically through the year.

Cold limit: USDA 8-11 · RHS H4 (-6–35°C)

Watch for — Frost dieback: In zones 7 and below, stems die back in hard frosts. Mulch the root zone in autumn, avoid pruning in autumn (which stimulates frost-tender growth), and site plants against a south-facing wall for extra warmth.

What rosemary's hardiness rating actually means

Yes — rosemary is genuinely cold hardy. Rated RHS H4 and USDA 8-11, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 8-11 — 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 −10 to −5 °C. Rosemary is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for rosemary as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 rosemary go outside or overwinter — and where?

Plant it out within USDA 8-11 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 rosemary can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Rosemary hardiness — frequently asked questions

Is rosemary cold hardy?

Yes — rosemary is genuinely cold hardy. Rated RHS H4 and USDA 8-11, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Rosemary is hardy across USDA 8-11; 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 rosemary can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Rosemary is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is rosemary?

Rosemary is rated USDA 8-11 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can rosemary survive winter outside?

Plant it out within USDA 8-11 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 rosemary below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.