Cold hardiness & minimum temperature

Is Lobb's Bulbophyllum (Bulbophyllum lobbii)cold hardy? Hardiness zone & min temp

Also called Lobb's Cirrhopetalum.

More about lobb's bulbophyllum

About Lobb's Bulbophyllum

Bulbophyllum lobbii · also called Lobb's Cirrhopetalum · flowering

Bulbophyllum lobbii is a widespread Southeast Asian epiphyte bearing large, solitary, nodding flowers in shades of yellow to tawny gold, often with a delicately hinged, quivering lip that moves in the breeze. A warm, humidity-loving grower, it does well mounted or in a basket with bright shade and steady moisture, and is one of the more forgiving large-flowered Bulbophyllums for beginners.

Cold limit: USDA 11-12 (warm greenhouse or indoor culture) · RHS H1b (18-30°C)

What lobb's bulbophyllum's hardiness rating actually means

Lobb's Bulbophyllum 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 (warm greenhouse or indoor culture) — 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). Lobb's Bulbophyllum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Lobb's Bulbophyllum hardiness — frequently asked questions

Is lobb's bulbophyllum cold hardy?

Lobb's Bulbophyllum 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. Lobb's Bulbophyllum can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (warm greenhouse or indoor culture)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature lobb's bulbophyllum can survive?

What hardiness zone is lobb's bulbophyllum?

Lobb's Bulbophyllum is rated USDA 11-12 (warm greenhouse or indoor culture) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can lobb's bulbophyllum 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 lobb's bulbophyllum 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.