Cold hardiness & minimum temperature

Is Aglaonema Unyamanee (Aglaonema 'Unyamanee')cold hardy? Hardiness zone & min temp

Also called Unyamanee Aglaonema.

More about aglaonema unyamanee

About Aglaonema Unyamanee

Aglaonema 'Unyamanee' · also called Unyamanee Aglaonema · houseplant

Aglaonema 'Unyamanee' is a bold Thai hybrid with large green leaves densely speckled in pink and cream, often with rose-red veins and stems. The heavy variegation needs bright indirect light to stay vibrant. A statement foliage plant that is still forgiving, thriving on warmth, even moisture and shelter from cold drafts.

Cold limit: USDA 10-12 (grown as a houseplant in most US and UK homes) · RHS H1b (18-27°C)

Watch for — Yellowing leaves: Overwatering or cold drafts. Let the soil surface dry between waterings and keep it warm.

What aglaonema unyamanee's hardiness rating actually means

Aglaonema Unyamanee 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 (grown as a houseplant in most US and UK 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). Aglaonema Unyamanee has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Aglaonema Unyamanee hardiness — frequently asked questions

Is aglaonema unyamanee cold hardy?

Aglaonema Unyamanee 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. Aglaonema Unyamanee can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (grown as a houseplant in most US and UK homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature aglaonema unyamanee can survive?

What hardiness zone is aglaonema unyamanee?

Aglaonema Unyamanee is rated USDA 10-12 (grown as a houseplant in most US and UK homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can aglaonema unyamanee 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 aglaonema unyamanee 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.