Cold hardiness & minimum temperature

Is Homalomena 'Emerald Gem' (Homalomena rubescens 'Emerald Gem')cold hardy? Hardiness zone & min temp

Also called Emerald Gem, Emerald Gem Homalomena.

More about homalomena 'emerald gem'

About Homalomena 'Emerald Gem'

Homalomena rubescens 'Emerald Gem' · also called Emerald Gem, Emerald Gem Homalomena · houseplant

Homalomena 'Emerald Gem' is a glossy, heart-leaved tropical aroid forming a tidy, bushy clump of deep-green leaves on reddish stems. Sometimes called the Emerald Gem, it is tough, shade-tolerant and easy, much like a Philodendron. Warm rooms, steady moisture and protection from cold and direct sun keep its lustrous foliage full and healthy indoors.

Cold limit: USDA 10-12 (indoor in most US homes) · RHS H1b (18-27°C)

Watch for — Yellowing lower leaves: Often overwatering or cold, soggy soil. Let the surface dry between waterings and ensure good drainage.

What homalomena 'emerald gem''s hardiness rating actually means

Homalomena 'Emerald Gem' 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 US 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). Homalomena 'Emerald Gem' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Homalomena 'Emerald Gem' hardiness — frequently asked questions

Is homalomena 'emerald gem' cold hardy?

Homalomena 'Emerald Gem' 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. Homalomena 'Emerald Gem' can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature homalomena 'emerald gem' can survive?

What hardiness zone is homalomena 'emerald gem'?

Homalomena 'Emerald Gem' is rated USDA 10-12 (indoor in most US homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can homalomena 'emerald gem' 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 homalomena 'emerald gem' 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.