Cold hardiness & minimum temperature

Is Rocket Mixed snapdragon (Antirrhinum majus 'Rocket Mixed')cold hardy? Hardiness zone & min temp

Also called Rocket Mixed snapdragon, Rocket Series snapdragon, Tall mixed snapdragon.

More about rocket mixed snapdragon

About Rocket Mixed snapdragon

Antirrhinum majus 'Rocket Mixed' · also called Rocket Mixed snapdragon, Rocket Series snapdragon · flowering

Rocket Mixed is a classic tall snapdragon series producing vigorous, heat-tolerant spikes in a wide range of colours including red, pink, orange, yellow, white, and purple. Growing to 90 cm, it is a top choice for professional cut flower growers and large cutting gardens. Cool-season blooming is most prolific; it flowers again in autumn where summers are mild.

Cold limit: USDA 7-10 · RHS H3 (7–21°C)

What rocket mixed snapdragon's hardiness rating actually means

Rocket Mixed snapdragon 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. Rocket Mixed snapdragon shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for rocket mixed snapdragon 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 rocket mixed snapdragon 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 rocket mixed snapdragon 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 rocket mixed snapdragon

Rocket Mixed snapdragon 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.

Rocket Mixed snapdragon hardiness — frequently asked questions

Is rocket mixed snapdragon cold hardy?

Rocket Mixed snapdragon 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) rocket mixed snapdragon can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature rocket mixed snapdragon can survive?

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

What hardiness zone is rocket mixed snapdragon?

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

Can rocket mixed snapdragon 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 rocket mixed snapdragon 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.