Cold hardiness & minimum temperature

Is Cup-Shaped Wittrockia (Wittrockia cyathiformis)cold hardy? Hardiness zone & min temp

Also called Cup Wittrockia.

More about cup-shaped wittrockia

About Cup-Shaped Wittrockia

Wittrockia cyathiformis · also called Cup Wittrockia · tropical

A lesser-known Brazilian bromeliad with the typical Wittrockia form — a broad, cup-shaped rosette of spiny-edged leaves and a central flower spike. It thrives in warm, humid conditions with bright, indirect light. As a bromeliad it is broadly considered pet-safe, though spiny edges pose a physical hazard.

Cold limit: USDA 10-12 (indoor-only in most US homes) · RHS H1b (15-30°C)

What cup-shaped wittrockia's hardiness rating actually means

Cup-Shaped Wittrockia 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-only 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). Cup-Shaped Wittrockia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Cup-Shaped Wittrockia hardiness — frequently asked questions

Is cup-shaped wittrockia cold hardy?

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

What is the minimum temperature cup-shaped wittrockia can survive?

What hardiness zone is cup-shaped wittrockia?

Cup-Shaped Wittrockia is rated USDA 10-12 (indoor-only 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 cup-shaped wittrockia 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 cup-shaped wittrockia 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.