Cold hardiness & minimum temperature

Is Clematis florida 'Sieboldii' (Clematis florida 'Sieboldii')cold hardy? Hardiness zone & min temp

Also called Siebold's clematis, passion flower clematis.

More about clematis florida 'sieboldii'

About Clematis florida 'Sieboldii'

Clematis florida 'Sieboldii' · also called Siebold's clematis, passion flower clematis · flowering

Clematis florida 'Sieboldii' is a striking deciduous-to-semi-evergreen climber with passion-flower-like blooms: creamy-white tepals around a dense central boss of rich purple staminodes. Flowering through summer, it is slightly more tender than most clematis and is often grown in a sheltered spot or large container in cool-temperate gardens.

Cold limit: USDA 6-9 (give winter shelter at the colder end) · RHS H4 (-10 to 27°C)

Watch for — Winter cold damage: Less hardy than typical clematis; in cold areas grow against a warm wall, in a sheltered courtyard or as a container plant moved to frost-free shelter.

What clematis florida 'sieboldii''s hardiness rating actually means

Yes — clematis florida 'sieboldii' is genuinely cold hardy. Rated RHS H4 and USDA 6-9 (give winter shelter at the colder end), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 6-9 (give winter shelter at the colder end) — 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 −10 to −5 °C. Clematis florida 'Sieboldii' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for clematis florida 'sieboldii' as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 florida 'sieboldii' go outside or overwinter — and where?

Plant it out within USDA 6-9 (give winter shelter at the colder end) 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 florida 'sieboldii' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Clematis florida 'Sieboldii' hardiness — frequently asked questions

Is clematis florida 'sieboldii' cold hardy?

Yes — clematis florida 'sieboldii' is genuinely cold hardy. Rated RHS H4 and USDA 6-9 (give winter shelter at the colder end), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Clematis florida 'Sieboldii' is hardy across USDA 6-9 (give winter shelter at the colder end); 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 florida 'sieboldii' can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Clematis florida 'Sieboldii' is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is clematis florida 'sieboldii'?

Clematis florida 'Sieboldii' is rated USDA 6-9 (give winter shelter at the colder end) and RHS H4 — Hardy in an average winter across much of the temperate world.

Can clematis florida 'sieboldii' survive winter outside?

Plant it out within USDA 6-9 (give winter shelter at the colder end) 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 florida 'sieboldii' below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.