Cold hardiness & minimum temperature

Is Biting Porroglossum (Porroglossum mordax)cold hardy? Hardiness zone & min temp

Also called Biting Porroglossum.

More about biting porroglossum

About Biting Porroglossum

Porroglossum mordax · also called Biting Porroglossum · tropical

A miniature cool-to-intermediate epiphytic orchid from Andean cloud forests, named for its particularly responsive hinged labellum that 'bites' closed on pollinators. It bears successive small flowers on hairy stems and requires high humidity and cool temperatures. A terrarium or cool greenhouse environment is necessary for success indoors.

Cold limit: USDA 10–11 · RHS H1c (9–20 °C)

Watch for — Temperature intolerance in warm homes: Consistent temperatures above 22 °C cause leaf yellowing and halt flowering. A cool basement grow space, refrigerated terrarium, or air-conditioned orchid room is needed; standard living-room temperatures are typically too warm.

What biting porroglossum's hardiness rating actually means

Biting Porroglossum 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10–11 — 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 5 °C (and never frost). Biting Porroglossum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for biting porroglossum as it gets too cold:

Below about about 5 °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 biting porroglossum go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 biting porroglossum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Biting Porroglossum hardiness — frequently asked questions

Is biting porroglossum cold hardy?

Biting Porroglossum 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. Biting Porroglossum can only live outside year-round in genuinely frost-free climates (roughly USDA 10–11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature biting porroglossum can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Biting Porroglossum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is biting porroglossum?

Biting Porroglossum is rated USDA 10–11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can biting porroglossum survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 biting porroglossum below its minimum temperature?

Below about about 5 °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.