Cold hardiness & minimum temperature

Is Mathilde's Rock Jasmine (Androsace mathildae)cold hardy? Hardiness zone & min temp

Also called Mathilde's rock jasmine, Mathilde's androsace.

More about mathilde's rock jasmine

About Mathilde's Rock Jasmine

Androsace mathildae · also called Mathilde's rock jasmine, Mathilde's androsace · flowering

Androsace mathildae is an extremely rare cushion-forming alpine endemic to the high limestone peaks of the central Apennines in Italy, found only above 2,350 m on Gran Sasso and Majella. It produces compact, silvery-hairy rosettes bearing small white to pale-pink flowers in late spring and demands near-perfect sharp drainage with protection from winter wet. As a true high-alpine, it thrives in cool summers and must never sit in waterlogged soil, making raised tufa crevices or alpine house cultivation the safest approach in UK gardens. Androsace is not listed by the ASPCA; as no pet-safety data is confirmed, treat it as mildly toxic and keep away from cats and dogs as a precaution.

Cold limit: USDA 4-7 · RHS H6 (-25 to 20°C)

Watch for — Cushion rot (Botrytis / fungal collar rot): The most serious threat: stagnant moisture at the crown, especially in winter, causes rapid blackening and collapse of rosettes. Ensure overhead dryness and place a grit collar around the cushion base.

What mathilde's rock jasmine's hardiness rating actually means

Yes — mathilde's rock jasmine is genuinely cold hardy. Rated RHS H6 and USDA 4-7, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 4-7 — 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 −20 to −15 °C. Mathilde's Rock Jasmine is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for mathilde's rock jasmine as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 mathilde's rock jasmine go outside or overwinter — and where?

Plant it out within USDA 4-7 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 mathilde's rock jasmine can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Mathilde's Rock Jasmine hardiness — frequently asked questions

Is mathilde's rock jasmine cold hardy?

Yes — mathilde's rock jasmine is genuinely cold hardy. Rated RHS H6 and USDA 4-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Mathilde's Rock Jasmine is hardy across USDA 4-7; 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 mathilde's rock jasmine can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Mathilde's Rock Jasmine is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is mathilde's rock jasmine?

Mathilde's Rock Jasmine is rated USDA 4-7 and RHS H6 — Hardy throughout the UK and northern Europe.

Can mathilde's rock jasmine survive winter outside?

Plant it out within USDA 4-7 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 mathilde's rock jasmine below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.