Cold hardiness & minimum temperature

Is Cascade Purple Aubrieta (Aubrieta 'Cascade Purple')cold hardy? Hardiness zone & min temp

Also called Cascade Purple Aubrieta, Purple Rock Cress.

More about cascade purple aubrieta

About Cascade Purple Aubrieta

Aubrieta 'Cascade Purple' · also called Cascade Purple Aubrieta, Purple Rock Cress · flowering

A vigorous, mat-forming perennial that smothers itself in rich purple flowers each spring. Ideal for walls, rockeries, and slopes, it cascades attractively over edges and thrives in alkaline, sharply drained soil in full sun. Trim back hard after flowering to keep it compact and encourage a possible second flush.

Cold limit: USDA 4–8 · RHS H6 (-15 to 25°C)

What cascade purple aubrieta's hardiness rating actually means

Yes — cascade purple aubrieta is genuinely cold hardy. Rated RHS H6 and USDA 4–8, 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 4–8 — 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. Cascade Purple Aubrieta is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for cascade purple aubrieta 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 cascade purple aubrieta go outside or overwinter — and where?

Plant it out within USDA 4–8 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 cascade purple aubrieta can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Cascade Purple Aubrieta hardiness — frequently asked questions

Is cascade purple aubrieta cold hardy?

Yes — cascade purple aubrieta is genuinely cold hardy. Rated RHS H6 and USDA 4–8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Cascade Purple Aubrieta is hardy across USDA 4–8; 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 cascade purple aubrieta can survive?

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

What hardiness zone is cascade purple aubrieta?

Cascade Purple Aubrieta is rated USDA 4–8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can cascade purple aubrieta survive winter outside?

Plant it out within USDA 4–8 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 cascade purple aubrieta 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.