Cold hardiness & minimum temperature

Is Lesser Sea Spurrey (Spergularia marina)cold hardy? Hardiness zone & min temp

Also called Lesser Sea Spurrey, Salt-marsh Sand Spurrey, Lesser Sea-spurrey.

More about lesser sea spurrey

About Lesser Sea Spurrey

Spergularia marina · also called Lesser Sea Spurrey, Salt-marsh Sand Spurrey · flowering

Spergularia marina is an annual or short-lived perennial halophyte of saltmarshes, sea walls, muddy shingle, and increasingly the salted verges of inland roads across Europe and North America. It produces clusters of small, deep pink flowers (5–8 mm) from June to September atop spreading, glandular-hairy stems. As a true halophyte, saline substrate is not merely tolerated but required for best performance; it outcompetes neighbours through salt-tolerance rather than vigour. This species has no ASPCA toxicity listing and is classified as mildly-toxic as a precautionary measure.

Cold limit: USDA 4-9 · RHS H5 (-5–25°C)

What lesser sea spurrey's hardiness rating actually means

Yes — lesser sea spurrey is genuinely cold hardy. Rated RHS H5 and USDA 4-9, 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 4-9 — 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. Lesser Sea Spurrey is built for winter — once established it takes hard frost and snow in its stride.

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

Plant it out within USDA 4-9 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 lesser sea spurrey can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Lesser Sea Spurrey hardiness — frequently asked questions

Is lesser sea spurrey cold hardy?

Yes — lesser sea spurrey is genuinely cold hardy. Rated RHS H5 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Lesser Sea Spurrey is hardy across USDA 4-9; 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 lesser sea spurrey can survive?

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

What hardiness zone is lesser sea spurrey?

Lesser Sea Spurrey is rated USDA 4-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can lesser sea spurrey survive winter outside?

Plant it out within USDA 4-9 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 lesser sea spurrey 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.