Cold hardiness & minimum temperature

Is Evergreen Candytuft (Iberis sempervirens)cold hardy? Hardiness zone & min temp

Also called Evergreen candytuft, Perennial candytuft, Edging candytuft.

More about evergreen candytuft

About Evergreen Candytuft

Iberis sempervirens · also called Evergreen candytuft, Perennial candytuft · flowering

Iberis sempervirens is a spreading, woody-based evergreen sub-shrub native to the rocky hillsides and scrubland of southern Europe, from the Iberian Peninsula east to Turkey. It forms a low, dense mound of narrow dark-green leaves that is smothered in flat-topped, pure-white flower heads from mid-spring to early summer. The single most important care task is a light but firm trim immediately after flowering to keep the plant compact and prolong its productive life. The toxicity status with respect to pets is uncertain — Iberis is not on the ASPCA list, but the Brassicaceae family can cause gastrointestinal irritation, so treat with caution around pets.

Cold limit: USDA 3-9 · RHS H5 (-15 to 35°C)

Watch for — Crown rot: Caused by waterlogged soil or excessive moisture at the base; ensure sharp drainage and avoid mulching right up to the woody stems. Most common on clay soils in wet winters.

What evergreen candytuft's hardiness rating actually means

Yes — evergreen candytuft is genuinely cold hardy. Rated RHS H5 and USDA 3-9, 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 3-9 — 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. Evergreen Candytuft is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for evergreen candytuft 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 evergreen candytuft go outside or overwinter — and where?

Plant it out within USDA 3-9 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 evergreen candytuft can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Evergreen Candytuft hardiness — frequently asked questions

Is evergreen candytuft cold hardy?

Yes — evergreen candytuft is genuinely cold hardy. Rated RHS H5 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Evergreen Candytuft is hardy across USDA 3-9; 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 evergreen candytuft can survive?

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

What hardiness zone is evergreen candytuft?

Evergreen Candytuft is rated USDA 3-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can evergreen candytuft survive winter outside?

Plant it out within USDA 3-9 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 evergreen candytuft 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.