Cold hardiness & minimum temperature

Is Glandular Rosularia (Rosularia adenotricha)cold hardy? Hardiness zone & min temp

Also called Glandular Rosularia, Glandular-hairy Rosularia.

More about glandular rosularia

About Glandular Rosularia

Rosularia adenotricha · also called Glandular Rosularia, Glandular-hairy Rosularia · houseplant

Rosularia adenotricha is a small, densely glandular-hairy Crassulaceae succulent from rocky montane habitats in Turkey and adjacent regions. Its sticky, glandular leaves form neat rosettes that trap dust and debris. It thrives in full sun with very sharp drainage and cool, dry winters, making it an excellent choice for alpine troughs, raised beds, or bright indoor sills.

Cold limit: USDA 6–9 · RHS H5 (-5–28°C)

What glandular rosularia's hardiness rating actually means

Yes — glandular rosularia is genuinely cold hardy. Rated RHS H5 and USDA 6–9, 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 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 −15 to −10 °C. Glandular Rosularia is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for glandular 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 glandular rosularia 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 glandular rosularia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Glandular Rosularia hardiness — frequently asked questions

Is glandular rosularia cold hardy?

Yes — glandular rosularia is genuinely cold hardy. Rated RHS H5 and USDA 6–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Glandular Rosularia 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 glandular rosularia can survive?

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

What hardiness zone is glandular rosularia?

Glandular Rosularia is rated USDA 6–9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can glandular rosularia 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 glandular 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.