Cold hardiness & minimum temperature

Is Yellow False Jasmine (Gelsemium sempervirens)cold hardy? Hardiness zone & min temp

Also called Carolina Jessamine, Evening Trumpetflower, Woodbine.

More about yellow false jasmine

About Yellow False Jasmine

Gelsemium sempervirens · also called Carolina Jessamine, Evening Trumpetflower · flowering

Yellow False Jasmine is an evergreen twining vine native to the southeastern United States, producing masses of fragrant yellow trumpet flowers in late winter to spring. Despite its common name and appearance it is unrelated to true jasmine. Extremely toxic — all parts including nectar can be lethal to people and animals.

Cold limit: USDA 7-10 · RHS H3 (−10 to 35°C)

Watch for — Scale insects: Soft brown scale can colonise stems. Treat with horticultural oil in late winter or remove by hand.

What yellow false jasmine's hardiness rating actually means

Yellow False Jasmine is half-hardy (RHS H3). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H3 means: Half-hardy — comes through mild UK winters outside but is killed by a hard freeze. On the US scale that maps to USDA 7-10 — 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 −5 to 1 °C — a light, short frost only. Yellow False Jasmine shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for yellow false jasmine as it gets too cold:

Down to roughly about −5 to 1 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can yellow false jasmine go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 7-10 or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 yellow false jasmine can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H3 figure above.

Frost protection for borderline yellow false jasmine

Yellow False Jasmine is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Yellow False Jasmine hardiness — frequently asked questions

Is yellow false jasmine cold hardy?

Yellow False Jasmine is half-hardy (RHS H3). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 7-10 (and sheltered UK gardens) yellow false jasmine can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature yellow false jasmine can survive?

Minimum survivable temperature is roughly about −5 to 1 °C — a light, short frost only. Yellow False Jasmine shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is yellow false jasmine?

Yellow False Jasmine is rated USDA 7-10 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can yellow false jasmine survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 7-10 or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect yellow false jasmine from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.