Cold hardiness & minimum temperature

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

Also called Autumn Joy sedum, stonecrop.

More about hylotelephium 'autumn joy'

About Hylotelephium 'Autumn Joy'

Hylotelephium 'Autumn Joy' · also called Autumn Joy sedum, stonecrop · flowering

'Autumn Joy' is a clump-forming hardy sedum prized for fleshy grey-green leaves and broad flower heads that open pink in late summer, deepen to coppery-red, then fade to rust over winter. This drought-tolerant, sun-loving perennial is a magnet for bees and butterflies and needs almost no care once established in lean, free-draining soil.

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

Watch for — Crown and root rot: Waterlogged or heavy clay soil rots the crown over winter. Improve drainage with grit and never let the plant sit in standing water.

What hylotelephium 'autumn joy''s hardiness rating actually means

Yes — hylotelephium 'autumn joy' 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. Hylotelephium 'Autumn Joy' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hylotelephium 'autumn joy' 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 hylotelephium 'autumn joy' 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 hylotelephium 'autumn joy' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Hylotelephium 'Autumn Joy' hardiness — frequently asked questions

Is hylotelephium 'autumn joy' cold hardy?

Yes — hylotelephium 'autumn joy' 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. Hylotelephium 'Autumn Joy' 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 hylotelephium 'autumn joy' can survive?

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

What hardiness zone is hylotelephium 'autumn joy'?

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

Can hylotelephium 'autumn joy' 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 hylotelephium 'autumn joy' 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.