Cold hardiness & minimum temperature

Is Artillery Plant (Pilea microphylla)cold hardy? Hardiness zone & min temp

Also called Artillery Plant, Artillery Fern, Rockweed, Gunpowder Plant, Angeloweed.

More about artillery plant

About Artillery Plant

Pilea microphylla · also called Artillery Plant, Artillery Fern · houseplant

The artillery plant (Pilea microphylla) is a fine-textured, fern-like trailing houseplant in the nettle family, named for the way it puffs out pollen. It wants bright indirect light, consistently moist soil, and humidity above 50 percent. ASPCA lists it as non-toxic to cats, dogs, and horses, making it a genuinely pet-safe choice.

Cold limit: USDA 11a-12b (18-24 C)

What artillery plant's hardiness rating actually means

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

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

Artillery Plant hardiness — frequently asked questions

Is artillery plant cold hardy?

Artillery Plant 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. Artillery Plant can only live outside year-round in genuinely frost-free climates (roughly USDA 11a-12b); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature artillery plant can survive?

What hardiness zone is artillery plant?

Artillery Plant is rated USDA 11a-12b and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can artillery plant 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 artillery plant 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.