Cold hardiness & minimum temperature

Is Clematis 'Ernest Markham' (Clematis 'Ernest Markham')cold hardy? Hardiness zone & min temp

Also called Ernest Markham clematis, magenta clematis.

More about clematis 'ernest markham'

About Clematis 'Ernest Markham'

Clematis 'Ernest Markham' · also called Ernest Markham clematis, magenta clematis · flowering

Clematis 'Ernest Markham' is a vigorous deciduous climber bearing rich glowing magenta-red flowers with a velvety sheen from midsummer into autumn. Usually grown as Pruning Group 3, it flowers on new wood and is cut back hard in late winter. It flowers most freely in plenty of sun, with the roots kept cool and shaded.

Cold limit: USDA 4-9 · RHS H6 (-20 to 25°C)

Watch for — Bare base: Hard annual pruning leaves the lower stems bare. Prune to 20-30 cm in late winter and screen the base with lower-growing companions.

What clematis 'ernest markham''s hardiness rating actually means

Yes — clematis 'ernest markham' 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 'Ernest Markham' is built for winter — once established it takes hard frost and snow in its stride.

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

Clematis 'Ernest Markham' hardiness — frequently asked questions

Is clematis 'ernest markham' cold hardy?

Yes — clematis 'ernest markham' 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 'Ernest Markham' 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 'ernest markham' can survive?

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

What hardiness zone is clematis 'ernest markham'?

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

Can clematis 'ernest markham' 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 'ernest markham' 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.