Cold hardiness & minimum temperature

Is Anthurium watermaliense (Anthurium watermaliense)cold hardy? Hardiness zone & min temp

Also called black anthurium, Watermal anthurium.

More about anthurium watermaliense

About Anthurium watermaliense

Anthurium watermaliense · also called black anthurium, Watermal anthurium · tropical

Anthurium watermaliense is a striking aroid from Colombian and Central American rainforests, famous for its near-black, deep maroon spathe and bold strap-shaped green leaves. Often sold as the black anthurium, it wants bright indirect light, an airy epiphytic mix, sustained warmth, and high humidity. Steady, evenly moist roots and good drainage produce the dramatic dark blooms it is grown for.

Cold limit: USDA 11-12 (indoor in most US homes) · RHS H1b (18-28°C)

What anthurium watermaliense's hardiness rating actually means

Anthurium watermaliense 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 11-12 (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). Anthurium watermaliense has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Anthurium watermaliense hardiness — frequently asked questions

Is anthurium watermaliense cold hardy?

Anthurium watermaliense 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. Anthurium watermaliense can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (indoor in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature anthurium watermaliense can survive?

What hardiness zone is anthurium watermaliense?

Anthurium watermaliense is rated USDA 11-12 (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 anthurium watermaliense 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 anthurium watermaliense 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.