Cold hardiness & minimum temperature

Is Star of Bethlehem Orchid (Angraecum sesquipedale)cold hardy? Hardiness zone & min temp

Also called Darwin's Orchid, Comet Orchid.

More about star of bethlehem orchid

About Star of Bethlehem Orchid

Angraecum sesquipedale · also called Darwin's Orchid, Comet Orchid · flowering

This Madagascan epiphyte is famous for ivory, star-shaped winter flowers trailing a foot-long nectar spur. Darwin predicted a moth with a matching tongue must pollinate it, vindicated decades later by the hawk moth Xanthopan morganii. A warm-growing orchid, it wants bright light, steady warmth, high humidity, and a thorough wet-dry watering cycle in coarse bark.

Cold limit: USDA 10-12 (indoor in most US homes) · RHS H1b (18-30°C)

Watch for — Bud blast (buds drop before opening): Caused by sudden drops in humidity, temperature swings, drafts, or letting the roots dry out while in bud. Keep conditions warm, humid, and stable through the winter flowering window.

What star of bethlehem orchid's hardiness rating actually means

Star of Bethlehem Orchid 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 10-12 (indoor in most US 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). Star of Bethlehem Orchid has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Star of Bethlehem Orchid hardiness — frequently asked questions

Is star of bethlehem orchid cold hardy?

Star of Bethlehem Orchid 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. Star of Bethlehem Orchid can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature star of bethlehem orchid can survive?

What hardiness zone is star of bethlehem orchid?

Star of Bethlehem Orchid is rated USDA 10-12 (indoor in most US homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can star of bethlehem orchid 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 star of bethlehem orchid 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.