Cold hardiness & minimum temperature

Is Golden-flowered Rosularia (Rosularia chrysantha)cold hardy? Hardiness zone & min temp

Also called Golden-flowered Rosularia, Golden Rosularia.

More about golden-flowered rosularia

About Golden-flowered Rosularia

Rosularia chrysantha · also called Golden-flowered Rosularia, Golden Rosularia · houseplant

Rosularia chrysantha is a charming alpine succulent from Turkey and the Caucasus, distinguished by its bright golden-yellow flowers that emerge in summer on slender stems above compact, fleshy rosettes. It appreciates full sun, sharp drainage, and minimal watering, thriving in rockeries, alpine troughs, or sunny indoor windowsills with cool, dry winter conditions.

Cold limit: USDA 5–9 · RHS H5 (-8–28°C)

Watch for — Crown rot in wet or cold-wet conditions: Water accumulating in the rosette, especially combined with cold temperatures, rapidly causes crown rot. Ensure rosettes are protected from prolonged rain in winter; use an alpine house or cloche if needed.

What golden-flowered rosularia's hardiness rating actually means

Yes — golden-flowered rosularia is genuinely cold hardy. Rated RHS H5 and USDA 5–9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 5–9 — 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 −15 to −10 °C. Golden-flowered Rosularia is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for golden-flowered rosularia as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 golden-flowered rosularia go outside or overwinter — and where?

Plant it out within USDA 5–9 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 golden-flowered rosularia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Golden-flowered Rosularia hardiness — frequently asked questions

Is golden-flowered rosularia cold hardy?

Yes — golden-flowered rosularia is genuinely cold hardy. Rated RHS H5 and USDA 5–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Golden-flowered Rosularia is hardy across USDA 5–9; 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 golden-flowered rosularia can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Golden-flowered Rosularia is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is golden-flowered rosularia?

Golden-flowered Rosularia is rated USDA 5–9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can golden-flowered rosularia survive winter outside?

Plant it out within USDA 5–9 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 golden-flowered rosularia below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.