Cold hardiness & minimum temperature

Is Cramer's Amazon celosia (Celosia spicata 'Cramer's Amazon')cold hardy? Hardiness zone & min temp

Also called Cramer's Amazon celosia, Wheat celosia 'Cramer's Amazon', Spiked cockscomb.

More about cramer's amazon celosia

About Cramer's Amazon celosia

Celosia spicata 'Cramer's Amazon' · also called Cramer's Amazon celosia, Wheat celosia 'Cramer's Amazon' · flowering

Cramer's Amazon celosia is a towering wheat-type celosia producing dense, upright magenta-pink flower spikes that fade gracefully to silvery-pink as they age. Highly sought-after by florists for its long vase life and dried flower versatility, it thrives in hot, sunny conditions with consistently moist, fertile soil. Blooms from midsummer to frost.

Cold limit: USDA 9–11 (grown as annual in cooler zones) · RHS H1c (18–35°C)

Watch for — Stunted growth from cold: Celosia is heat-demanding; transplanting before soil reaches 18°C causes sulking, yellowing, and checked growth. Wait until night temperatures are reliably above 15°C before planting out.

What cramer's amazon celosia's hardiness rating actually means

Cramer's Amazon celosia 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 9–11 (grown as annual in cooler 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 °C (and never frost). Cramer's Amazon celosia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for cramer's amazon celosia 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 cramer's amazon celosia 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 cramer's amazon celosia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Cramer's Amazon celosia hardiness — frequently asked questions

Is cramer's amazon celosia cold hardy?

Cramer's Amazon celosia 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. Cramer's Amazon celosia can only live outside year-round in genuinely frost-free climates (roughly USDA 9–11 (grown as annual in cooler zones)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature cramer's amazon celosia can survive?

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

What hardiness zone is cramer's amazon celosia?

Cramer's Amazon celosia is rated USDA 9–11 (grown as annual in cooler zones) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can cramer's amazon celosia 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 cramer's amazon celosia 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.