Cold hardiness & minimum temperature

Is Monosolenium tenerum (Monosolenium tenerum)cold hardy? Hardiness zone & min temp

Also called pellia, false pellia.

More about monosolenium tenerum

About Monosolenium tenerum

Monosolenium tenerum · also called pellia, false pellia · tropical

Monosolenium tenerum, sold as pellia, is a thick, brittle thalloid liverwort grown fully submerged in freshwater aquariums. It forms dense, branching cushions of dark green crystalline foliage. Unrooted, it must be tied to rock or wood until it anchors. Brighter than most mosses, it grows fast in nutrient-rich, CO2-supplemented tanks but breaks apart easily.

Cold limit: USDA Not applicable (tropical/temperate aquarium plant, indoor) · RHS H1a (18-28°C)

What monosolenium tenerum's hardiness rating actually means

Monosolenium tenerum 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA Not applicable (tropical/temperate 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 above about 15 °C (warm, never cold). Monosolenium tenerum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for monosolenium tenerum as it gets too cold:

Below about above about 15 °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 monosolenium tenerum go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 monosolenium tenerum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Monosolenium tenerum hardiness — frequently asked questions

Is monosolenium tenerum cold hardy?

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

What is the minimum temperature monosolenium tenerum can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Monosolenium tenerum has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is monosolenium tenerum?

Monosolenium tenerum is rated USDA Not applicable (tropical/temperate aquarium plant, indoor) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can monosolenium tenerum survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 monosolenium tenerum below its minimum temperature?

Below about above about 15 °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.