Cold hardiness & minimum temperature

Is Profusion orange zinnia (Zinnia elegans 'Profusion Orange')cold hardy? Hardiness zone & min temp

Also called Profusion Orange zinnia, Profusion zinnia.

More about profusion orange zinnia

About Profusion orange zinnia

Zinnia elegans 'Profusion Orange' · also called Profusion Orange zinnia, Profusion zinnia · flowering

An interspecific hybrid annual (Z. elegans × Z. angustifolia) that forms dense, self-branching mounds smothered in 2-inch vivid orange blooms all summer. Exceptionally heat- and drought-tolerant once established, highly resistant to powdery mildew, and requires no deadheading to rebloom. Ideal for borders, containers, and pollinator gardens.

Cold limit: USDA 2–11 (grown as a warm-season annual) · RHS H1c (frost-tender annual; sow after last frost) (18–35°C)

What profusion orange zinnia's hardiness rating actually means

Profusion orange zinnia is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 2–11 (grown as a warm-season annual) — 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 °C (and never frost). Profusion orange zinnia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for profusion orange zinnia as it gets too cold:

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can profusion orange zinnia go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 profusion orange zinnia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Profusion orange zinnia hardiness — frequently asked questions

Is profusion orange zinnia cold hardy?

Profusion orange zinnia is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Profusion orange zinnia can only live outside year-round in genuinely frost-free climates (roughly USDA 2–11 (grown as a warm-season annual)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature profusion orange zinnia can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Profusion orange zinnia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is profusion orange zinnia?

Profusion orange zinnia is rated USDA 2–11 (grown as a warm-season annual) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can profusion orange zinnia survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to profusion orange zinnia below its minimum temperature?

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.