Cold hardiness & minimum temperature

Is White-Branch Wax Plant (Hoya leucorampha)cold hardy? Hardiness zone & min temp

Also called White-branch wax plant, Wax plant.

More about white-branch wax plant

About White-Branch Wax Plant

Hoya leucorampha · also called White-branch wax plant, Wax plant · tropical

Hoya leucorampha is a tropical epiphytic vine native to Southeast Asia, named for its distinctively pale, whitish stems ('leuco' meaning white, 'rampha' relating to branches). It thrives in bright indirect light with well-draining, airy soil that mimics its epiphytic woodland habitat, and the single most important care rule is to allow the potting medium to dry between waterings to prevent root rot. Like all Hoya species, it is listed as non-toxic to cats and dogs by the ASPCA.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1b (16–30°C)

What white-branch wax plant's hardiness rating actually means

White-Branch Wax 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 10-12 (indoor in most climates) — 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). White-Branch Wax Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

White-Branch Wax Plant hardiness — frequently asked questions

Is white-branch wax plant cold hardy?

White-Branch Wax 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. White-Branch Wax Plant can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature white-branch wax plant can survive?

What hardiness zone is white-branch wax plant?

White-Branch Wax Plant is rated USDA 10-12 (indoor in most climates) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can white-branch wax 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 white-branch wax 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.