Cold hardiness & minimum temperature

Is Heuchera 'Key Lime Pie' (Heuchera 'Key Lime Pie')cold hardy? Hardiness zone & min temp

Also called Coral Bells 'Key Lime Pie', Alumroot 'Key Lime Pie'.

More about heuchera 'key lime pie'

About Heuchera 'Key Lime Pie'

Heuchera 'Key Lime Pie' · also called Coral Bells 'Key Lime Pie', Alumroot 'Key Lime Pie' · flowering

Heuchera 'Key Lime Pie' is a distinctive evergreen perennial with rounded, lime-green to chartreuse leaves that brighten shaded spots in the garden. It produces delicate white flower spikes in late spring. Tolerant of moderate drought once established, it is easy to grow and is listed by the ASPCA as non-toxic to pets.

Cold limit: USDA 4-9 · RHS H6 (5-25°C)

Watch for — Winter heaving: Repeated freezing and thawing can lift the shallow crown; firm back down after frost and apply a light gravel or bark mulch around the base.

What heuchera 'key lime pie''s hardiness rating actually means

Yes — heuchera 'key lime pie' 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. Heuchera 'Key Lime Pie' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for heuchera 'key lime pie' 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 heuchera 'key lime pie' 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 heuchera 'key lime pie' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Heuchera 'Key Lime Pie' hardiness — frequently asked questions

Is heuchera 'key lime pie' cold hardy?

Yes — heuchera 'key lime pie' 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. Heuchera 'Key Lime Pie' 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 heuchera 'key lime pie' can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Heuchera 'Key Lime Pie' is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is heuchera 'key lime pie'?

Heuchera 'Key Lime Pie' is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can heuchera 'key lime pie' 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 heuchera 'key lime pie' 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.