Cold hardiness & minimum temperature

Is Peruvian zinnia (Zinnia peruviana)cold hardy? Hardiness zone & min temp

Also called Peruvian zinnia, field zinnia, redstar zinnia, wild zinnia.

More about peruvian zinnia

About Peruvian zinnia

Zinnia peruviana · also called Peruvian zinnia, field zinnia · flowering

A heat-loving annual native to Mexico, Central America, and South America bearing single, daisy-like flowers in warm shades of red, orange, yellow, and deep magenta from midsummer through autumn. Taller and more open-branching than modern hybrid zinnias, it is extremely heat- and drought-tolerant, attracts butterflies abundantly, and performs well in naturalistic or meadow-style plantings.

Cold limit: USDA 2-11 · RHS H1c (15–35°C)

What peruvian zinnia's hardiness rating actually means

Peruvian 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 — 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). Peruvian zinnia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Peruvian zinnia hardiness — frequently asked questions

Is peruvian zinnia cold hardy?

Peruvian 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. Peruvian zinnia can only live outside year-round in genuinely frost-free climates (roughly USDA 2-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature peruvian zinnia can survive?

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

What hardiness zone is peruvian zinnia?

Peruvian zinnia is rated USDA 2-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can peruvian 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 peruvian 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.