Cold hardiness & minimum temperature

Is Clematis 'Bill MacKenzie' (Clematis 'Bill MacKenzie')cold hardy? Hardiness zone & min temp

Also called Bill MacKenzie clematis, yellow lantern clematis.

More about clematis 'bill mackenzie'

About Clematis 'Bill MacKenzie'

Clematis 'Bill MacKenzie' · also called Bill MacKenzie clematis, yellow lantern clematis · flowering

A vigorous tangutica-type clematis with large, nodding bright yellow lantern flowers and thick waxy petals from midsummer well into autumn, followed by silky silver seedheads—often flowers and seedheads together. A Group 3 climber pruned hard in late winter, it is robust, long-flowering and holds an RHS Award of Garden Merit.

Cold limit: USDA 4-9 · RHS H6 (-25 to 32°C)

Watch for — Self-seeding: Abundant seedheads scatter viable seed. Remove seedheads if you want to prevent volunteer seedlings, or leave them for winter display.

What clematis 'bill mackenzie''s hardiness rating actually means

Yes — clematis 'bill mackenzie' 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. Clematis 'Bill MacKenzie' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for clematis 'bill mackenzie' 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 clematis 'bill mackenzie' 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 clematis 'bill mackenzie' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Clematis 'Bill MacKenzie' hardiness — frequently asked questions

Is clematis 'bill mackenzie' cold hardy?

Yes — clematis 'bill mackenzie' 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. Clematis 'Bill MacKenzie' 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 clematis 'bill mackenzie' can survive?

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

What hardiness zone is clematis 'bill mackenzie'?

Clematis 'Bill MacKenzie' is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can clematis 'bill mackenzie' 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 clematis 'bill mackenzie' 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.