Cold hardiness & minimum temperature

Is Night-Blooming Cereus (Selenicereus grandiflorus)cold hardy? Hardiness zone & min temp

Also called Night-Blooming Cereus, Queen of the Night, Large-Flowered Cactus.

More about night-blooming cereus

About Night-Blooming Cereus

Selenicereus grandiflorus · also called Night-Blooming Cereus, Queen of the Night · flowering

Selenicereus grandiflorus, Queen of the Night, is a climbing, scrambling epiphytic cactus from Central America and the Caribbean with slender, ribbed, sometimes aerial-rooting stems. It is celebrated for enormous, intensely fragrant white flowers that open for a single night. It prefers bright indirect light, moderate watering, warmth, and support to climb, rewarding patience with a spectacular fleeting bloom.

Cold limit: USDA 10-11 (indoor or under glass in cooler regions) · RHS H1b (18-29°C)

Watch for — No flowers: Plants must be mature and given enough light plus a cooler, drier winter rest to bloom. Be patient, brighten the position, and provide a winter rest period to trigger the night flowers.

What night-blooming cereus's hardiness rating actually means

Night-Blooming Cereus 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 10-11 (indoor or under glass in cooler regions) — 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). Night-Blooming Cereus has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for night-blooming cereus 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 night-blooming cereus 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 night-blooming cereus can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Night-Blooming Cereus hardiness — frequently asked questions

Is night-blooming cereus cold hardy?

Night-Blooming Cereus 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. Night-Blooming Cereus can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor or under glass in cooler regions)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature night-blooming cereus can survive?

What hardiness zone is night-blooming cereus?

Night-Blooming Cereus is rated USDA 10-11 (indoor or under glass in cooler regions) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can night-blooming cereus 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 night-blooming cereus 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.