Cold hardiness & minimum temperature

Is Paz's Wax Plant (Hoya paziae)cold hardy? Hardiness zone & min temp

Also called Paz's wax plant, Paz hoya.

More about paz's wax plant

About Paz's Wax Plant

Hoya paziae · also called Paz's wax plant, Paz hoya · houseplant

Hoya paziae is a rare epiphytic vining species from the Philippines, grown for its attractive dark-green leaves and small, star-shaped, fragrant flowers borne in characteristic umbel clusters. Like most hoyas, it needs bright indirect light, a fast-draining epiphytic mix, and careful watering that allows the medium to dry between sessions to prevent root rot. The single most critical care point is never removing spent flower spurs (peduncles), as these rebloom year after year. Hoya paziae is regarded as non-toxic to cats and dogs, consistent with ASPCA guidance for the Hoya genus.

Cold limit: USDA 11-12 (indoor in most climates) · RHS H1b (18-30°C)

What paz's wax plant's hardiness rating actually means

Paz's 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 11-12 (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). Paz's Wax Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for paz's 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 paz's 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 paz's 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.

Paz's Wax Plant hardiness — frequently asked questions

Is paz's wax plant cold hardy?

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

What is the minimum temperature paz's wax plant can survive?

What hardiness zone is paz's wax plant?

Paz's Wax Plant is rated USDA 11-12 (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 paz's 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 paz's 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.