Cold hardiness & minimum temperature

Is Philodendron Silver Sword (Philodendron hastatum 'Silver Sword')cold hardy? Hardiness zone & min temp

Also called Silver Sword Philodendron, Philodendron hastatum, Silver Sword.

More about philodendron silver sword

About Philodendron Silver Sword

Philodendron hastatum 'Silver Sword' · also called Silver Sword Philodendron, Philodendron hastatum · tropical

Philodendron Silver Sword is a fast-growing climbing aroid prized for its metallic, silvery-blue arrow-shaped leaves. Give it bright indirect light, a moss pole, warmth, and high humidity, and let the top inch of soil dry between waterings. The ASPCA lists Philodendron as toxic to cats and dogs, so keep it out of reach.

Cold limit: USDA 10a-11b (18-29 C)

What philodendron silver sword's hardiness rating actually means

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

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

Philodendron Silver Sword hardiness — frequently asked questions

Is philodendron silver sword cold hardy?

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

What is the minimum temperature philodendron silver sword can survive?

What hardiness zone is philodendron silver sword?

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

Can philodendron silver sword 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 philodendron silver sword 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.