Cold hardiness & minimum temperature

Is Achimenes erecta (Achimenes erecta)cold hardy? Hardiness zone & min temp

Also called Cupid's bower, upright achimenes.

More about achimenes erecta

About Achimenes erecta

Achimenes erecta · also called Cupid's bower, upright achimenes · flowering

Achimenes erecta is a species hot water plant from Central America bearing small, bright scarlet-red tubular flowers over slender, often trailing stems through summer. Grown from tiny scaly rhizomes, it wants warmth, steady moisture, and humid air to bloom. After flowering it dies back to dormant rhizomes stored dry and cool, then restarted with warm water in spring.

Cold limit: USDA 9-11 (lifted/stored dormant elsewhere) · RHS H1b (18-27°C)

Watch for — Premature dormancy: Cold or letting the mix dry out can stop growth early. Keep warmth and even moisture through summer to prolong flowering.

What achimenes erecta's hardiness rating actually means

Achimenes erecta 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 9-11 (lifted/stored dormant elsewhere) — 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 10 °C (sustained cold below this is damaging). Achimenes erecta has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for achimenes erecta as it gets too cold:

Below about about 10 °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 achimenes erecta go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °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 achimenes erecta can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Achimenes erecta hardiness — frequently asked questions

Is achimenes erecta cold hardy?

Achimenes erecta 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. Achimenes erecta can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (lifted/stored dormant elsewhere)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature achimenes erecta can survive?

What hardiness zone is achimenes erecta?

Achimenes erecta is rated USDA 9-11 (lifted/stored dormant elsewhere) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can achimenes erecta survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °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 achimenes erecta below its minimum temperature?

Below about about 10 °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.