Cold hardiness & minimum temperature

Is Calathea Rufibarba Blue Grass (Goeppertia rufibarba 'Blue Grass')cold hardy? Hardiness zone & min temp

Also called blue grass calathea, blue grass furry feather.

More about calathea rufibarba blue grass

About Calathea Rufibarba Blue Grass

Goeppertia rufibarba 'Blue Grass' · also called blue grass calathea, blue grass furry feather · houseplant

A furry-feather prayer plant with long, wavy-edged lance-shaped leaves that are deep green above and flushed burgundy beneath, carried on fuzzy reddish stems. The 'Blue Grass' form shows a cool blue-green cast. It wants steady moisture, warmth and high humidity, stays compact, and is non-toxic to cats and dogs.

Cold limit: USDA 11-12 (indoor in most US homes) · RHS H1b (18-27°C)

Watch for — Limp or curling leaves: Underwatering or dry air; keep soil evenly moist and humidity up, and check for draughts.

What calathea rufibarba blue grass's hardiness rating actually means

Calathea Rufibarba Blue Grass 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 (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). Calathea Rufibarba Blue Grass has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for calathea rufibarba blue grass 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 calathea rufibarba blue grass 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 calathea rufibarba blue grass can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Calathea Rufibarba Blue Grass hardiness — frequently asked questions

Is calathea rufibarba blue grass cold hardy?

Calathea Rufibarba Blue Grass 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. Calathea Rufibarba Blue Grass can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature calathea rufibarba blue grass can survive?

What hardiness zone is calathea rufibarba blue grass?

Calathea Rufibarba Blue Grass is rated USDA 11-12 (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 calathea rufibarba blue grass 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 calathea rufibarba blue grass 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.