Cold hardiness & minimum temperature

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

Also called Lobb's Orchid, Yellow Bulbophyllum.

More about lobb's bulbophyllum

About Lobb's Bulbophyllum

Bulbophyllum lobbii · also called Lobb's Orchid, Yellow Bulbophyllum · tropical

A variable Southeast Asian epiphyte bearing solitary, large, creamy-yellow flowers with finely spotted petals and a movable lip that rocks in the slightest breeze. Collected by Thomas Lobb in the 1840s, it remains a collector favourite. ASPCA lists Bulbophyllum as non-toxic. Grows well in warm, humid, bright conditions.

Cold limit: USDA 11-12 (warm greenhouse or indoor warm room; no cold tolerance) · RHS H1a (15-30°C)

Watch for — Slow rhizome spread stalling: Insufficient warmth (below 18°C) slows rhizome extension and new pseudobulb production; maintain warm temperatures year-round.

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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 11-12 (warm greenhouse or indoor warm room; no cold tolerance) — 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 above about 15 °C (warm, never cold). 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 above about 15 °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 above 15 °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 H1a 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 warm room; no cold tolerance)); everywhere else it is a houseplant that summers out at most.

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

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Lobb's Bulbophyllum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is lobb's bulbophyllum?

Lobb's Bulbophyllum is rated USDA 11-12 (warm greenhouse or indoor warm room; no cold tolerance) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can lobb's bulbophyllum survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 above about 15 °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.