Cold hardiness & minimum temperature

Is Greek Oregano (Origanum vulgare subsp. hirtum)cold hardy? Hardiness zone & min temp

Also called True Oregano, Winter Marjoram.

More about greek oregano

About Greek Oregano

Origanum vulgare subsp. hirtum · also called True Oregano, Winter Marjoram · herb

Greek oregano is the most pungent, peppery oregano and the standard for Mediterranean cooking, with fuzzy grey-green leaves and white summer flowers. A hardy perennial sub-shrub, it demands full sun and sharp drainage to concentrate its essential oils, and grows weak and flavourless in shade or rich, damp soil.

Cold limit: USDA 5-10 (hardy culinary perennial) · RHS H5 (-12 to 30°C)

What greek oregano's hardiness rating actually means

Yes — greek oregano is genuinely cold hardy. Rated RHS H5 and USDA 5-10 (hardy culinary perennial), 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 5-10 (hardy culinary perennial) — 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. Greek Oregano is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for greek oregano 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 greek oregano go outside or overwinter — and where?

Plant it out within USDA 5-10 (hardy culinary perennial) 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 greek oregano can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Greek Oregano hardiness — frequently asked questions

Is greek oregano cold hardy?

Yes — greek oregano is genuinely cold hardy. Rated RHS H5 and USDA 5-10 (hardy culinary perennial), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Greek Oregano is hardy across USDA 5-10 (hardy culinary perennial); 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 greek oregano can survive?

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

What hardiness zone is greek oregano?

Greek Oregano is rated USDA 5-10 (hardy culinary perennial) and RHS H5 — Hardy in most of the UK and in cold winters.

Can greek oregano survive winter outside?

Plant it out within USDA 5-10 (hardy culinary perennial) 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 greek oregano 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.