Cold hardiness & minimum temperature

Is Creeping Borage (Borago pygmaea)cold hardy? Hardiness zone & min temp

Also called creeping borage, prostrate borage.

More about creeping borage

About Creeping Borage

Borago pygmaea · also called creeping borage, prostrate borage · herb

Borago pygmaea is a sprawling, short-lived perennial borage from Corsica and Sardinia, lower and more lax than annual borage. It bears nodding, pale sky-blue star flowers over rough, bristly leaves from summer into autumn, spreading by lax stems and self-seeding. A bee magnet for partial shade and moist, well-drained soil in cottage and wildlife gardens.

Cold limit: USDA 6-9 · RHS H4 (-5 to 28°C)

Watch for — Rot in wet, heavy soil: Lax sprawling stems and crown rot in waterlogged ground. Plant in free-draining soil and avoid winter wet.

What creeping borage's hardiness rating actually means

Yes — creeping borage is genuinely cold hardy. Rated RHS H4 and USDA 6-9, 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 6-9 — 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 −10 to −5 °C. Creeping Borage is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for creeping borage 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 creeping borage go outside or overwinter — and where?

Plant it out within USDA 6-9 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 creeping borage can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Creeping Borage hardiness — frequently asked questions

Is creeping borage cold hardy?

Yes — creeping borage is genuinely cold hardy. Rated RHS H4 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Creeping Borage is hardy across USDA 6-9; 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 creeping borage can survive?

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

What hardiness zone is creeping borage?

Creeping Borage is rated USDA 6-9 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can creeping borage survive winter outside?

Plant it out within USDA 6-9 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 creeping borage 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.