Cold hardiness & minimum temperature

Is Burnet Saxifrage (Pimpinella saxifraga)cold hardy? Hardiness zone & min temp

Also called Burnet Saxifrage, Lesser Burnet, Solidstem Burnet Saxifrage.

More about burnet saxifrage

About Burnet Saxifrage

Pimpinella saxifraga · also called Burnet Saxifrage, Lesser Burnet · herb

Pimpinella saxifraga is a slender, taproot-forming perennial herb in the carrot family (Apiaceae), native to dry grasslands, road verges, and chalk downland across the UK, Europe, and western Asia. It produces flat-topped umbels of tiny white flowers from June to September above a basal rosette of pinnate leaves, with smaller, finer stem leaves — a trait used to distinguish it from the similar greater burnet saxifrage (Pimpinella major). Leaves and seeds are edible with a mild anise-parsley flavour, and the root has a long history of medicinal use. Toxicity to cats and dogs is not confirmed by ASPCA; classified as mildly-toxic due to the presence of furanocoumarins in the Apiaceae family.

Cold limit: USDA 4-8 · RHS H7 (-20 to 26°C)

What burnet saxifrage's hardiness rating actually means

Yes — burnet saxifrage 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. Burnet Saxifrage is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for burnet saxifrage 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 burnet saxifrage 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 burnet saxifrage can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Burnet Saxifrage hardiness — frequently asked questions

Is burnet saxifrage cold hardy?

Yes — burnet saxifrage 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. Burnet Saxifrage 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 burnet saxifrage can survive?

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

What hardiness zone is burnet saxifrage?

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

Can burnet saxifrage 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 burnet saxifrage 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.