Cold hardiness & minimum temperature

Is Hedge Bedstraw (Galium mollugo)cold hardy? Hardiness zone & min temp

Also called Hedge Bedstraw, False Baby's Breath, White Bedstraw.

More about hedge bedstraw

About Hedge Bedstraw

Galium mollugo · also called Hedge Bedstraw, False Baby's Breath · flowering

Hedge bedstraw is a scrambling native perennial of the Rubiaceae family, found across the UK in hedgerows, road verges, rough grassland, and scrub margins. Dense, frothy clusters of small creamy-white flowers from June to September make it a valuable pollinator plant, rated by the RHS as Perfect for Pollinators. It spreads freely by rhizomes and self-seeds, so site it where it has room to roam or divide regularly. Toxicity to pets has conflicting minor reports; it is not formally listed as safe by ASPCA, so treat as mildly toxic with pets.

Cold limit: USDA 4-8 · RHS H7 (-20–25 °C)

What hedge bedstraw's hardiness rating actually means

Yes — hedge bedstraw is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 4-8 — 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 below about −20 °C. Hedge Bedstraw is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hedge bedstraw as it gets too cold:

It tolerates winter lows to about −20 °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 hedge bedstraw go outside or overwinter — and where?

Plant it out within USDA 4-8 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 hedge bedstraw can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Hedge Bedstraw hardiness — frequently asked questions

Is hedge bedstraw cold hardy?

Yes — hedge bedstraw is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Hedge Bedstraw is hardy across USDA 4-8; 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 hedge bedstraw can survive?

Minimum survivable temperature is roughly below about −20 °C. Hedge Bedstraw is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is hedge bedstraw?

Hedge Bedstraw is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can hedge bedstraw survive winter outside?

Plant it out within USDA 4-8 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 hedge bedstraw below its minimum temperature?

It tolerates winter lows to about −20 °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.