Cold hardiness & minimum temperature

Is Humboldt's Caladium (Caladium humboldtii)cold hardy? Hardiness zone & min temp

Also called Mini Caladium, Miniature Caladium, Dwarf Fancy-Leaf Caladium.

More about humboldt's caladium

About Humboldt's Caladium

Caladium humboldtii · also called Mini Caladium, Miniature Caladium · tropical

Caladium humboldtii is a compact Araceae species from South America, producing small, heart-shaped white leaves splashed and veined with bright green. Its diminutive size makes it ideal for terrariums or small pots. It goes dormant in cool or dry periods. All parts are toxic to pets and humans due to calcium oxalate crystals.

Cold limit: USDA 10-11 (tubers must be stored frost-free) · RHS H1c (20-30°C)

Watch for — Root rot: Tubers are susceptible to rot in cold, wet soil. Ensure warm temperatures (above 20°C) and good drainage at all times.

What humboldt's caladium's hardiness rating actually means

Humboldt's Caladium 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-11 (tubers must be stored frost-free) — 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 5 °C (and never frost). Humboldt's Caladium has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for humboldt's caladium as it gets too cold:

Below about about 5 °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 humboldt's caladium go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 humboldt's caladium can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Humboldt's Caladium hardiness — frequently asked questions

Is humboldt's caladium cold hardy?

Humboldt's Caladium 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. Humboldt's Caladium can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (tubers must be stored frost-free)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature humboldt's caladium can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Humboldt's Caladium has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is humboldt's caladium?

Humboldt's Caladium is rated USDA 10-11 (tubers must be stored frost-free) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can humboldt's caladium survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 humboldt's caladium below its minimum temperature?

Below about about 5 °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.