Cold hardiness & minimum temperature

Is Impatiens hawkeri 'SunPatiens Spreading White' (Impatiens hawkeri 'SunPatiens Spreading White')cold hardy? Hardiness zone & min temp

Also called SunPatiens Spreading White, Spreading New Guinea Impatiens.

More about impatiens hawkeri 'sunpatiens spreading white'

About Impatiens hawkeri 'SunPatiens Spreading White'

Impatiens hawkeri 'SunPatiens Spreading White' · also called SunPatiens Spreading White, Spreading New Guinea Impatiens · flowering

A spreading, sun-tolerant New Guinea-type impatiens from the SunPatiens range, smothered in clean white flowers over lush green foliage. Its vigorous, wide-spreading habit makes it ideal for filling beds, large containers and baskets in full sun or part shade. It needs rich, consistently moist soil and regular feeding, and offers strong heat and downy-mildew tolerance.

Cold limit: USDA 10-12 (grown as a frost-tender annual in most regions) · RHS H2 (16-29°C)

What impatiens hawkeri 'sunpatiens spreading white''s hardiness rating actually means

Impatiens hawkeri 'SunPatiens Spreading White' 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 10-12 (grown as a frost-tender annual in most 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 1 to 5 °C — tolerates cold but no real frost. Impatiens hawkeri 'SunPatiens Spreading White' shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for impatiens hawkeri 'sunpatiens spreading white' 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 impatiens hawkeri 'sunpatiens spreading white' go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-12 (grown as a frost-tender annual in most 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 impatiens hawkeri 'sunpatiens spreading white' 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 impatiens hawkeri 'sunpatiens spreading white'

Impatiens hawkeri 'SunPatiens Spreading White' 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.

Impatiens hawkeri 'SunPatiens Spreading White' hardiness — frequently asked questions

Is impatiens hawkeri 'sunpatiens spreading white' cold hardy?

Impatiens hawkeri 'SunPatiens Spreading White' 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 10-12 (grown as a frost-tender annual in most regions) (and sheltered UK gardens) impatiens hawkeri 'sunpatiens spreading white' can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature impatiens hawkeri 'sunpatiens spreading white' can survive?

What hardiness zone is impatiens hawkeri 'sunpatiens spreading white'?

Impatiens hawkeri 'SunPatiens Spreading White' is rated USDA 10-12 (grown as a frost-tender annual in most regions) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can impatiens hawkeri 'sunpatiens spreading white' survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-12 (grown as a frost-tender annual in most 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 impatiens hawkeri 'sunpatiens spreading white' 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.