Cold hardiness & minimum temperature

Is French Lavender (Lavandula dentata)cold hardy? Hardiness zone & min temp

Also called Fringed Lavender.

More about french lavender

About French Lavender

Lavandula dentata · also called Fringed Lavender · herb

French (fringed) lavender has distinctive toothed grey-green leaves, a soft balsamic-camphor scent, and pale lavender flower spikes topped by small bracts, blooming over a very long season. It is more tender than English lavender, needing full sun, sharp drainage, and frost protection in cold climates, where it is best grown in pots and overwintered under cover.

Cold limit: USDA 8-11 (frost-tender; overwinter under glass in colder regions) · RHS H3 (10-27°C)

Watch for — Frost damage: Less hardy than English lavender, it is killed or set back by hard frost; grow in containers that can be moved into a frost-free, bright spot for winter.

What french lavender's hardiness rating actually means

French Lavender 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 8-11 (frost-tender; overwinter under glass in colder regions) — 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. French Lavender shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for french lavender 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 french lavender go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (frost-tender; overwinter under glass in colder regions) 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 french lavender 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 french lavender

French Lavender 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.

French Lavender hardiness — frequently asked questions

Is french lavender cold hardy?

French Lavender 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 8-11 (frost-tender; overwinter under glass in colder regions) (and sheltered UK gardens) french lavender can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature french lavender can survive?

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

What hardiness zone is french lavender?

French Lavender is rated USDA 8-11 (frost-tender; overwinter under glass in colder regions) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can french lavender survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (frost-tender; overwinter under glass in colder regions) 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 french lavender 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.