Cold hardiness & minimum temperature

Is Campsis radicans (Campsis radicans)cold hardy? Hardiness zone & min temp

Also called trumpet vine, trumpet creeper, cow-itch vine.

More about campsis radicans

About Campsis radicans

Campsis radicans · also called trumpet vine, trumpet creeper · flowering

A vigorous deciduous climber native to the southeastern US, prized for clusters of large orange-to-scarlet trumpet flowers from summer to autumn that draw hummingbirds and bees. It self-clings by aerial rootlets, scaling walls and fences fast. Robust and hardy, it can be invasive and suckering, so plant where its rampant spread can be controlled.

Cold limit: USDA 4-9 · RHS H5 (-20-35°C)

What campsis radicans's hardiness rating actually means

Yes — campsis radicans is genuinely cold hardy. Rated RHS H5 and USDA 4-9, 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 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 −15 to −10 °C. Campsis radicans is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for campsis radicans 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 campsis radicans 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 campsis radicans can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Campsis radicans hardiness — frequently asked questions

Is campsis radicans cold hardy?

Yes — campsis radicans is genuinely cold hardy. Rated RHS H5 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Campsis radicans 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 campsis radicans can survive?

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

What hardiness zone is campsis radicans?

Campsis radicans is rated USDA 4-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can campsis radicans 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 campsis radicans 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.