Cold hardiness & minimum temperature

Is Lemmon's marigold (Tagetes lemmonii)cold hardy? Hardiness zone & min temp

Also called Lemmon's marigold, Copper Canyon daisy, mountain marigold, Mexican bush marigold.

More about lemmon's marigold

About Lemmon's marigold

Tagetes lemmonii · also called Lemmon's marigold, Copper Canyon daisy · flowering

A sprawling, aromatic evergreen subshrub from the mountains of Arizona and Mexico that delivers a spectacular display of golden-yellow daisy-like flowers in autumn and mild winters. Unlike annual marigolds, it forms a large, long-lived woody base. Exceptionally drought-tolerant and heat-resilient once established, it is popular in Southwestern US and Mediterranean-climate gardens.

Cold limit: USDA 8-10 · RHS H2 (-5–38°C)

Watch for — Frost dieback in zone 8: Hard frosts below -5°C can kill stems to ground level. Cut back frosted wood in early spring; plants typically regenerate strongly from the root crown. Mulch the base in borderline zones.

What lemmon's marigold's hardiness rating actually means

Lemmon's marigold is half-hardy (RHS H2). 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 H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 8-10 — 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 1 to 5 °C — tolerates cold but no real frost. Lemmon's marigold shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for lemmon's marigold as it gets too cold:

Down to roughly about 1 to 5 °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 lemmon's marigold go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-10 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 lemmon's marigold can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline lemmon's marigold

Lemmon's marigold 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.

Lemmon's marigold hardiness — frequently asked questions

Is lemmon's marigold cold hardy?

Lemmon's marigold is half-hardy (RHS H2). 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 8-10 (and sheltered UK gardens) lemmon's marigold can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature lemmon's marigold can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Lemmon's marigold shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is lemmon's marigold?

Lemmon's marigold is rated USDA 8-10 and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can lemmon's marigold survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-10 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 lemmon's marigold 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.