Cold hardiness & minimum temperature

Is Verbena × hybrida 'Superbena Stormburst' (Verbena × hybrida 'Superbena Stormburst')cold hardy? Hardiness zone & min temp

Also called Superbena Stormburst Verbena, Bicolor Trailing Verbena.

More about verbena × hybrida 'superbena stormburst'

About Verbena × hybrida 'Superbena Stormburst'

Verbena × hybrida 'Superbena Stormburst' · also called Superbena Stormburst Verbena, Bicolor Trailing Verbena · flowering

'Superbena Stormburst' is a vigorous, trailing garden verbena bearing large clusters of lavender-pink florets streaked with darker veining. Bred for heat tolerance and strong mildew resistance, it spills generously from baskets and containers and blooms from spring to frost in full sun. Self-cleaning and floriferous, it needs only steady warmth, sun and sharp drainage.

Cold limit: USDA 9-11 (treated as a summer annual in colder zones) · RHS H3 (15-32°C)

What verbena × hybrida 'superbena stormburst''s hardiness rating actually means

Verbena × hybrida 'Superbena Stormburst' 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 9-11 (treated as a summer annual in colder zones) — 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. Verbena × hybrida 'Superbena Stormburst' shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for verbena × hybrida 'superbena stormburst' 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 verbena × hybrida 'superbena stormburst' go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (treated as a summer annual in colder zones) 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 verbena × hybrida 'superbena stormburst' 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 verbena × hybrida 'superbena stormburst'

Verbena × hybrida 'Superbena Stormburst' 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.

Verbena × hybrida 'Superbena Stormburst' hardiness — frequently asked questions

Is verbena × hybrida 'superbena stormburst' cold hardy?

Verbena × hybrida 'Superbena Stormburst' 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 9-11 (treated as a summer annual in colder zones) (and sheltered UK gardens) verbena × hybrida 'superbena stormburst' can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature verbena × hybrida 'superbena stormburst' can survive?

What hardiness zone is verbena × hybrida 'superbena stormburst'?

Verbena × hybrida 'Superbena Stormburst' is rated USDA 9-11 (treated as a summer annual in colder zones) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can verbena × hybrida 'superbena stormburst' survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (treated as a summer annual in colder zones) 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 verbena × hybrida 'superbena stormburst' 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.