Cold hardiness & minimum temperature

Is Hylotelephium 'Purple Emperor' (Hylotelephium 'Purple Emperor')cold hardy? Hardiness zone & min temp

Also called Purple Emperor sedum, purple stonecrop.

More about hylotelephium 'purple emperor'

About Hylotelephium 'Purple Emperor'

Hylotelephium 'Purple Emperor' · also called Purple Emperor sedum, purple stonecrop · flowering

'Purple Emperor' is a dark-leaved stonecrop grown as much for its smoky purple-black foliage as for the dusky pink flower heads it carries in late summer. The deep leaf colour intensifies in full sun, contrasting beautifully with the rose blooms and the bees they draw. It is compact, drought-tolerant and undemanding in lean, well-drained soil.

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

Watch for — Crown rot in wet soil: Winter waterlogging rots the crown. Plant on free-draining ground and add grit to heavy soils.

What hylotelephium 'purple emperor''s hardiness rating actually means

Yes — hylotelephium 'purple emperor' 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 'Purple Emperor' is built for winter — once established it takes hard frost and snow in its stride.

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

Hylotelephium 'Purple Emperor' hardiness — frequently asked questions

Is hylotelephium 'purple emperor' cold hardy?

Yes — hylotelephium 'purple emperor' 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 'Purple Emperor' 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 'purple emperor' can survive?

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

What hardiness zone is hylotelephium 'purple emperor'?

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

Can hylotelephium 'purple emperor' 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 'purple emperor' 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.