Cold hardiness & minimum temperature

Is Hoya lacunosa (Hoya lacunosa)cold hardy? Hardiness zone & min temp

Also called Cinnamon Hoya, Cinnamon-scented wax plant, Furry Hoya, Lacunosa wax plant.

More about hoya lacunosa

About Hoya lacunosa

Hoya lacunosa · also called Cinnamon Hoya, Cinnamon-scented wax plant · houseplant

Hoya lacunosa is a compact, trailing epiphytic wax plant prized for clusters of small, cinnamon-scented white flowers and dense, slightly sunken-veined foliage. Give it bright indirect light, let the airy mix dry out between waterings, and keep it warm. The ASPCA does not flag the Hoya genus as toxic, making it broadly pet-friendly.

Cold limit: USDA 10-11 (grown as a houseplant elsewhere; not frost-hardy) (16-29 C)

Watch for — Cold damage: Exposure below about 10 C (50 F) causes leaf yellowing and dropped flower buds. Keep away from cold draughts and unheated rooms, and bring outdoor plants in well before nights turn cold.

What hoya lacunosa's hardiness rating actually means

Hoya lacunosa 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 (grown as a houseplant elsewhere; not frost-hardy) — 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). Hoya lacunosa has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for hoya lacunosa 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 hoya lacunosa 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 hoya lacunosa can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Hoya lacunosa hardiness — frequently asked questions

Is hoya lacunosa cold hardy?

Hoya lacunosa 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. Hoya lacunosa can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (grown as a houseplant elsewhere; not frost-hardy)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature hoya lacunosa can survive?

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

What hardiness zone is hoya lacunosa?

Hoya lacunosa is rated USDA 10-11 (grown as a houseplant elsewhere; not frost-hardy) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can hoya lacunosa 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 hoya lacunosa 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.