Cold hardiness & minimum temperature

Is Palace Purple coral bells (Heuchera 'Palace Purple')cold hardy? Hardiness zone & min temp

Also called Palace Purple coral bells, Palace Purple heuchera.

More about palace purple coral bells

About Palace Purple coral bells

Heuchera 'Palace Purple' · also called Palace Purple coral bells, Palace Purple heuchera · flowering

Heuchera 'Palace Purple' is a landmark cultivar and 1991 Perennial Plant of the Year, bearing striking deep burgundy-purple, maple-shaped foliage that persists year-round in mild climates. Tiny white flowers appear on wiry stems in summer. It was pivotal in launching the coloured-foliage heuchera revolution and remains a versatile edging and container plant for partial shade.

Cold limit: USDA 4–9 · RHS H6 (−29 °C to 32 °C)

Watch for — Crown rot: Wet winters or mulch piled against the crown cause rot. Plant slightly proud of soil level, use gritty compost, and keep crowns exposed to air. Lift and divide congested plants every 3 years.

What palace purple coral bells's hardiness rating actually means

Yes — palace purple coral bells is genuinely cold hardy. Rated RHS H6 and USDA 4–9, 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 4–9 — 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 −20 to −15 °C. Palace Purple coral bells is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for palace purple coral bells 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 palace purple coral bells go outside or overwinter — and where?

Plant it out within USDA 4–9 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 palace purple coral bells can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Palace Purple coral bells hardiness — frequently asked questions

Is palace purple coral bells cold hardy?

Yes — palace purple coral bells is genuinely cold hardy. Rated RHS H6 and USDA 4–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Palace Purple coral bells is hardy across USDA 4–9; 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 palace purple coral bells can survive?

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

What hardiness zone is palace purple coral bells?

Palace Purple coral bells is rated USDA 4–9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can palace purple coral bells survive winter outside?

Plant it out within USDA 4–9 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 palace purple coral bells 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.