Cold hardiness & minimum temperature

Is Purple Wreath (Petrea volubilis)cold hardy? Hardiness zone & min temp

Also called Purple Wreath, Queen's Wreath, Sandpaper Vine, Blue Petrea.

More about purple wreath

About Purple Wreath

Petrea volubilis · also called Purple Wreath, Queen's Wreath · tropical

A spectacular flowering tropical vine from Central America and the Caribbean, bearing foot-long racemes of star-like violet flowers that rival wisteria in impact. The rough, sandpaper-textured leaves give it an alternative common name. Fast-growing and floriferous in full sun, it thrives in USDA zones 10–11 and tolerates brief light frost when established.

Cold limit: USDA 10–11 · RHS H1b (10–35°C)

Watch for — Frost damage: Tender to frost; established mature plants may tolerate brief temperatures to -1°C but young plants are highly susceptible. In borderline zones (9–10), plant against a sheltered south-facing wall and mulch the root zone heavily in winter.

What purple wreath's hardiness rating actually means

Purple Wreath 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 10–11 — 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). Purple Wreath has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Purple Wreath hardiness — frequently asked questions

Is purple wreath cold hardy?

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

What is the minimum temperature purple wreath can survive?

What hardiness zone is purple wreath?

Purple Wreath is rated USDA 10–11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can purple wreath 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 purple wreath 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.