Cold hardiness & minimum temperature

Is Hazel 'Red Filbert' (Corylus avellana 'Purpurea')cold hardy? Hardiness zone & min temp

Also called purple-leaf hazel, red filbert, ornamental hazel.

More about hazel 'red filbert'

About Hazel 'Red Filbert'

Corylus avellana 'Purpurea' · also called purple-leaf hazel, red filbert · edible

This purple-leaved hazel is an ornamental, edible-nut form of common hazel with deep red-purple spring foliage, purplish catkins and reddish husks. Hardy, easy and shade-tolerant, it suits hedges, woodland edges and mixed borders. Foliage colour holds best in full sun; nut yields are modest compared with dedicated cobnut cultivars.

Cold limit: USDA 4-8 · RHS H6 (-25 to 28°C)

What hazel 'red filbert''s hardiness rating actually means

Yes — hazel 'red filbert' is genuinely cold hardy. Rated RHS H6 and USDA 4-8, 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 4-8 — 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. Hazel 'Red Filbert' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hazel 'red filbert' 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 hazel 'red filbert' go outside or overwinter — and where?

Plant it out within USDA 4-8 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 hazel 'red filbert' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Hazel 'Red Filbert' hardiness — frequently asked questions

Is hazel 'red filbert' cold hardy?

Yes — hazel 'red filbert' is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Hazel 'Red Filbert' is hardy across USDA 4-8; 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 hazel 'red filbert' can survive?

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

What hardiness zone is hazel 'red filbert'?

Hazel 'Red Filbert' is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can hazel 'red filbert' survive winter outside?

Plant it out within USDA 4-8 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 hazel 'red filbert' 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.