Cold hardiness & minimum temperature

Is Aerangis biloba (Aerangis biloba)cold hardy? Hardiness zone & min temp

Also called Two-lobed Aerangis, African Star Orchid.

More about aerangis biloba

About Aerangis biloba

Aerangis biloba · also called Two-lobed Aerangis, African Star Orchid · flowering

Aerangis biloba is a West African monopodial epiphyte named for its notched, two-lobed leaf tips, bearing graceful pendent sprays of white star-shaped flowers with long curving nectar spurs that are fragrant at night. Grown mounted or in small baskets, it wants bright filtered light, warm conditions, steady even moisture, and high humidity to flower well indoors.

Cold limit: USDA 11-12 (grown indoors / greenhouse in most US and UK homes) · RHS H1b (18-30°C)

Watch for — Bud blast: Dry air or unstable conditions as the long-spurred buds form. Keep humidity high and temperatures steady through the autumn bloom cycle.

What aerangis biloba's hardiness rating actually means

Aerangis biloba 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 11-12 (grown indoors / greenhouse in most US and UK homes) — 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). Aerangis biloba has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Aerangis biloba hardiness — frequently asked questions

Is aerangis biloba cold hardy?

Aerangis biloba 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. Aerangis biloba can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (grown indoors / greenhouse in most US and UK homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature aerangis biloba can survive?

What hardiness zone is aerangis biloba?

Aerangis biloba is rated USDA 11-12 (grown indoors / greenhouse in most US and UK homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can aerangis biloba 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 aerangis biloba 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.