Cold hardiness & minimum temperature

Is Yellow Ice Plant (Delosperma nubigenum)cold hardy? Hardiness zone & min temp

Also called Cloud-Living Ice Plant, Lesotho Ice Plant, Hardy Yellow Delosperma.

More about yellow ice plant

About Yellow Ice Plant

Delosperma nubigenum · also called Cloud-Living Ice Plant, Lesotho Ice Plant · flowering

Delosperma nubigenum is a prostrate, mat-forming hardy succulent from Lesotho's highlands, bearing masses of bright yellow flowers in spring and early summer. Among the hardiest Delosperma species, it tolerates severe frost and snow. Its fleshy, bright green leaves turn red in cold weather. Not individually ASPCA-listed; treat as mildly toxic as a precaution.

Cold limit: USDA 4–9 · RHS H6 (-20–35°C)

Watch for — Winter root rot: Despite its frost hardiness, it is intolerant of wet soil in winter. In heavy clay soils, plant in raised beds or improve drainage with grit.

What yellow ice plant's hardiness rating actually means

Yes — yellow ice plant is genuinely cold hardy. Rated RHS H6 and USDA 4–9, 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 4–9 — 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 −20 to −15 °C. Yellow Ice Plant is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for yellow ice plant 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 yellow ice plant go outside or overwinter — and where?

Plant it out within USDA 4–9 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 yellow ice plant can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Yellow Ice Plant hardiness — frequently asked questions

Is yellow ice plant cold hardy?

Yes — yellow ice plant is genuinely cold hardy. Rated RHS H6 and USDA 4–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Yellow Ice Plant is hardy across USDA 4–9; 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 yellow ice plant can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Yellow Ice Plant is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is yellow ice plant?

Yellow Ice Plant is rated USDA 4–9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can yellow ice plant survive winter outside?

Plant it out within USDA 4–9 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 yellow ice plant 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.