Cold hardiness & minimum temperature

Is Yellow Monanthes (Monanthes icterica)cold hardy? Hardiness zone & min temp

Also called Yellow Monanthes.

More about yellow monanthes

About Yellow Monanthes

Monanthes icterica · also called Yellow Monanthes · houseplant

Yellow Monanthes is a rare annual succulent endemic to Tenerife and La Gomera in the Canary Islands. Unlike its perennial Monanthes relatives, it germinates in autumn, flowers in early spring, and sets seed by late May. Grow in bright indirect light with minimal winter water and fast-draining gritty soil.

Cold limit: USDA 10-11 · RHS H1b (5–25°C)

What yellow monanthes's hardiness rating actually means

Yellow Monanthes 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 10-11 — 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). Yellow Monanthes has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Yellow Monanthes hardiness — frequently asked questions

Is yellow monanthes cold hardy?

Yellow Monanthes 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. Yellow Monanthes can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature yellow monanthes can survive?

What hardiness zone is yellow monanthes?

Yellow Monanthes is rated USDA 10-11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can yellow monanthes 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 yellow monanthes 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.