Cold hardiness & minimum temperature

Is Sea Stork's Bill (Erodium maritimum)cold hardy? Hardiness zone & min temp

Also called Sea Stork's Bill, Sea Heron's Bill.

More about sea stork's bill

About Sea Stork's Bill

Erodium maritimum · also called Sea Stork's Bill, Sea Heron's Bill · flowering

Erodium maritimum is a small, native British and western European coastal perennial that forms flat rosettes pressed to the ground, supported by a deep taproot that anchors it in sandy dunes and rocky coastal clifftops. It produces tiny, pale lilac to almost white flowers from April to September and is one of the few Erodium species genuinely native to southern and western Britain. It demands very free-draining, sandy or stony soil in full sun and is highly tolerant of salt spray and exposure. Not documented as toxic; mildly-toxic classification used in the absence of an ASPCA species-level entry.

Cold limit: USDA 7-10 · RHS H4 (-10 to 25°C)

What sea stork's bill's hardiness rating actually means

Yes — sea stork's bill is genuinely cold hardy. Rated RHS H4 and USDA 7-10, 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 7-10 — 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. Sea Stork's Bill is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for sea stork's bill 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 sea stork's bill go outside or overwinter — and where?

Plant it out within USDA 7-10 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 stork's bill can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Frost protection for borderline sea stork's bill

Sea Stork's Bill is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes.
Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness.
Shelter new growth from late spring frosts with fleece if a hard night is forecast.

Sea Stork's Bill hardiness — frequently asked questions

Is sea stork's bill cold hardy?

Yes — sea stork's bill is genuinely cold hardy. Rated RHS H4 and USDA 7-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Sea Stork's Bill is hardy across USDA 7-10; 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 stork's bill can survive?

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

What hardiness zone is sea stork's bill?

Sea Stork's Bill is rated USDA 7-10 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can sea stork's bill survive winter outside?

Plant it out within USDA 7-10 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.

How do I protect sea stork's bill from frost?

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes. Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness. Shelter new growth from late spring frosts with fleece if a hard night is forecast.