Cold hardiness & minimum temperature

Is Micranthemum tweediei 'Monte Carlo' (Micranthemum tweediei 'Monte Carlo')cold hardy? Hardiness zone & min temp

Also called Monte Carlo plant, New Large-leaved baby tears.

More about micranthemum tweediei 'monte carlo'

About Micranthemum tweediei 'Monte Carlo'

Micranthemum tweediei 'Monte Carlo' · also called Monte Carlo plant, New Large-leaved baby tears · tropical

Micranthemum tweediei 'Monte Carlo' is a popular foreground carpeting plant valued as an easier alternative to dwarf baby tears. Small round leaves on creeping stems form a lush green lawn across the substrate. It carpets in moderate light and can manage without pressurised CO2, though CO2 and rich aquasoil give a faster, denser, more reliable carpet.

Cold limit: USDA Not applicable (tropical aquarium plant, indoor) · RHS H1b (20-26°C)

What micranthemum tweediei 'monte carlo''s hardiness rating actually means

Micranthemum tweediei 'Monte Carlo' 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 Not applicable (tropical aquarium plant, indoor) — 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). Micranthemum tweediei 'Monte Carlo' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for micranthemum tweediei 'monte carlo' 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 micranthemum tweediei 'monte carlo' 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 micranthemum tweediei 'monte carlo' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Micranthemum tweediei 'Monte Carlo' hardiness — frequently asked questions

Is micranthemum tweediei 'monte carlo' cold hardy?

Micranthemum tweediei 'Monte Carlo' 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. Micranthemum tweediei 'Monte Carlo' can only live outside year-round in genuinely frost-free climates (roughly USDA Not applicable (tropical aquarium plant, indoor)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature micranthemum tweediei 'monte carlo' can survive?

What hardiness zone is micranthemum tweediei 'monte carlo'?

Micranthemum tweediei 'Monte Carlo' is rated USDA Not applicable (tropical aquarium plant, indoor) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can micranthemum tweediei 'monte carlo' 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 micranthemum tweediei 'monte carlo' 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.