Cold hardiness & minimum temperature

Is Hardy Ice Plant (Delosperma cooperi)cold hardy? Hardiness zone & min temp

Also called Cooper's Ice Plant, Pink Carpet Ice Plant, Trailing Ice Plant.

More about hardy ice plant

About Hardy Ice Plant

Delosperma cooperi · also called Cooper's Ice Plant, Pink Carpet Ice Plant · flowering

Delosperma cooperi is a South African mat-forming succulent groundcover producing vivid magenta-pink daisy-like flowers from late spring through autumn. One of the hardiest Delosperma species, tolerating frost to around -15°C. Ideal for rock gardens, borders, or containers in full sun. Not individually listed by the ASPCA; treat as mildly toxic as a precaution.

Cold limit: USDA 5–9 · RHS H5 (-15–35°C)

Watch for — Root rot in winter: The most common failure; caused by waterlogged soil in cold, wet winters. Ensure excellent drainage or grow in raised beds.

What hardy ice plant's hardiness rating actually means

Yes — hardy ice plant 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. Hardy Ice Plant is built for winter — once established it takes hard frost and snow in its stride.

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

Hardy Ice Plant hardiness — frequently asked questions

Is hardy ice plant cold hardy?

Yes — hardy ice plant 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. Hardy Ice Plant 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 hardy ice plant can survive?

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

What hardiness zone is hardy ice plant?

Hardy Ice Plant is rated USDA 5–9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can hardy ice plant 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 hardy ice plant 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.