Cold hardiness & minimum temperature

Is Clematis (Clematis spp.)cold hardy? Hardiness zone & min temp

Also called Clematis, Leather flower, Virgin's bower, Old man's beard, Traveller's joy.

More about clematis

About Clematis

Clematis spp. · also called Clematis, Leather flower · flowering

Clematis is a deciduous or evergreen flowering climber prized for showy blooms on trellises, walls and fences. It thrives with sun on its foliage and shade on its roots. Important warning: Clematis is toxic to cats, dogs and horses per the ASPCA, so site it away from pets that chew foliage.

Cold limit: USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3) · RHS H5-H6 (hardy in most of the UK; varies by species and cultivar) (-10-24°C)

Watch for — Slime flux: A frothy, foul-smelling ooze seeps from the stems when bacteria enter through frost or mechanical damage to the woody tissue.

What clematis's hardiness rating actually means

Yes — clematis is genuinely cold hardy. Rated RHS H5 and USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3) — 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 −15 to −10 °C. Clematis is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for clematis as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 go outside or overwinter — and where?

Plant it out within USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3) 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 can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Clematis hardiness — frequently asked questions

Is clematis cold hardy?

Yes — clematis is genuinely cold hardy. Rated RHS H5 and USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Clematis is hardy across USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3); 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 can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Clematis is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is clematis?

Clematis is rated USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3) and RHS H5 — Hardy in most of the UK and in cold winters.

Can clematis survive winter outside?

Plant it out within USDA USDA Zones 4-9 (a few cultivars hardy to Zone 3) 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 below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.