Cold hardiness & minimum temperature

Is Strawberry globe amaranth (Gomphrena haageana)cold hardy? Hardiness zone & min temp

Also called Strawberry globe amaranth, haage globe amaranth, orange globe amaranth.

More about strawberry globe amaranth

About Strawberry globe amaranth

Gomphrena haageana · also called Strawberry globe amaranth, haage globe amaranth · flowering

Strawberry globe amaranth produces bright orange-red to strawberry-coloured papery flowerheads on sturdy, well-branched stems through summer and autumn. A heat- and drought-tolerant Central American annual, it thrives in full sun and poor, well-drained soils. Its intensely coloured, everlasting flowers are superb for fresh and dried arrangements.

Cold limit: USDA 9-11 (perennial), 2-11 (annual) · RHS H1c (18–40°C)

What strawberry globe amaranth's hardiness rating actually means

Strawberry globe amaranth 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 (perennial), 2-11 (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). Strawberry globe amaranth has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Strawberry globe amaranth hardiness — frequently asked questions

Is strawberry globe amaranth cold hardy?

Strawberry globe amaranth 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. Strawberry globe amaranth can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (perennial), 2-11 (annual)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature strawberry globe amaranth can survive?

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

What hardiness zone is strawberry globe amaranth?

Strawberry globe amaranth is rated USDA 9-11 (perennial), 2-11 (annual) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can strawberry globe amaranth 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 strawberry globe amaranth 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.