Cold hardiness & minimum temperature

Is Autumn Joy Stonecrop (Sedum 'Autumn Joy')cold hardy? Hardiness zone & min temp

Also called Herbstfreude, Showy Stonecrop.

More about autumn joy stonecrop

About Autumn Joy Stonecrop

Sedum 'Autumn Joy' · also called Herbstfreude, Showy Stonecrop · flowering

Sedum 'Autumn Joy' (Hylotelephium 'Herbstfreude') is a clump-forming hardy border perennial grown for its large, flat flower heads that open dusky pink in late summer and deepen to brick-red and russet through autumn. The fleshy blue-green foliage and seedheads provide long-season interest and feed late pollinators. Tough, drought-tolerant and easy in full sun and well-drained soil.

Cold limit: USDA 3-9 · RHS H7 (-34 to 30°C)

Watch for — Crown rot in wet winters: Heavy, waterlogged soil rots the crown over winter. Plant in sharply drained ground and avoid mulching directly over the crown.

What autumn joy stonecrop's hardiness rating actually means

Yes — autumn joy stonecrop is genuinely cold hardy. Rated RHS H7 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental 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 below about −20 °C. Autumn Joy Stonecrop is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for autumn joy stonecrop as it gets too cold:

It tolerates winter lows to about −20 °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 autumn joy stonecrop 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 autumn joy stonecrop can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Autumn Joy Stonecrop hardiness — frequently asked questions

Is autumn joy stonecrop cold hardy?

Yes — autumn joy stonecrop is genuinely cold hardy. Rated RHS H7 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Autumn Joy Stonecrop 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 autumn joy stonecrop can survive?

Minimum survivable temperature is roughly below about −20 °C. Autumn Joy Stonecrop is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is autumn joy stonecrop?

Autumn Joy Stonecrop is rated USDA 3-9 and RHS H7 — Hardy in the severest European continental winters.

Can autumn joy stonecrop 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 autumn joy stonecrop below its minimum temperature?

It tolerates winter lows to about −20 °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.