Cold hardiness & minimum temperature

Is Sea Purslane (Atriplex portulacoides)cold hardy? Hardiness zone & min temp

Also called Sea purslane, Lesser shrubby orache, Shrubby sea-purslane.

More about sea purslane

About Sea Purslane

Atriplex portulacoides · also called Sea purslane, Lesser shrubby orache · edible

Atriplex portulacoides is a low, spreading, evergreen subshrub native to saltmarshes and upper tidal mudflats around European coasts, including much of the British coastline. Its thick, succulent grey-green leaves are edible with a naturally salty, pleasantly crisp texture and are used raw in salads or lightly cooked as a seasoning vegetable. The most important care fact is maximum sun and free-draining or brackish-tolerant soil — it evolved in intertidal conditions and will not tolerate shade or heavy, waterlogged growing media. Not listed as toxic to pets by the ASPCA; moderation is advisable due to naturally high salt and oxalate content.

Cold limit: USDA 5-9 · RHS H5 (-15 to 30°C)

What sea purslane's hardiness rating actually means

Yes — sea purslane is genuinely cold hardy. Rated RHS H5 and USDA 5-9, 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 5-9 — 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. Sea Purslane is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for sea purslane 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 sea purslane go outside or overwinter — and where?

Plant it out within USDA 5-9 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 sea purslane can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Sea Purslane hardiness — frequently asked questions

Is sea purslane cold hardy?

Yes — sea purslane is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Sea Purslane is hardy across USDA 5-9; 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 sea purslane can survive?

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

What hardiness zone is sea purslane?

Sea Purslane is rated USDA 5-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can sea purslane survive winter outside?

Plant it out within USDA 5-9 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 sea purslane 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.