Cold hardiness & minimum temperature

Is Leopoldina Earth Star (Cryptanthus leopoldo-horstii)cold hardy? Hardiness zone & min temp

Also called Leopoldina Earth Star, Leopoldo-Horst's Earth Star.

More about leopoldina earth star

About Leopoldina Earth Star

Cryptanthus leopoldo-horstii · also called Leopoldina Earth Star, Leopoldo-Horst's Earth Star · tropical

Cryptanthus leopoldo-horstii (reclassified in current taxonomy as Forzzaea leopoldo-horstii) is a terrestrial bromeliad endemic to Brazil, belonging to a clade of Cryptanthus with notably attractive, often wine-red or dark-banded foliage. Like all earth stars it grows as a flat to slightly upright rosette on the forest floor, spreading by stoloniferous offsets. The most important care fact is that high ambient humidity is critical for this species — inadequate humidity causes leaf margins to brown and the plant's colour to diminish rapidly. The Cryptanthus genus (Earth Star) is listed as non-toxic to cats and dogs by the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (18-29°C)

Watch for — Brown leaf margins: The most common complaint with this species; caused by low humidity, fluoride in tap water, or cold draughts — raise humidity above 60%, switch to rainwater, and move away from air conditioning vents.

What leopoldina earth star's hardiness rating actually means

Leopoldina Earth Star 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 in most climates) — 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). Leopoldina Earth Star has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for leopoldina earth star 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 leopoldina earth star 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 leopoldina earth star can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Leopoldina Earth Star hardiness — frequently asked questions

Is leopoldina earth star cold hardy?

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

What is the minimum temperature leopoldina earth star can survive?

What hardiness zone is leopoldina earth star?

Leopoldina Earth Star is rated USDA 10-12 (indoor in most climates) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can leopoldina earth star 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 leopoldina earth star 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.