Cold hardiness & minimum temperature

Is Hayata's Stephania (Stephania hayatae)cold hardy? Hardiness zone & min temp

Also called Hayata's Stephania.

More about hayata's stephania

About Hayata's Stephania

Stephania hayatae · also called Hayata's Stephania · houseplant

Stephania hayatae is a peltate-leaved caudiciform vine from Taiwan and adjacent East Asia, grown by collectors for its distinctive shield-shaped leaves attached near the leaf centre and its large, partially exposed caudex (tuber). It needs warmth, bright indirect light, and a pronounced dry winter rest to thrive.

Cold limit: USDA 10-12 · RHS H1b (15–32°C)

Watch for — Caudex rot over winter: The most frequently fatal mistake. If the caudex is kept moist while dormant (no vine growth), fungal rot rapidly sets in. Maintain a strict dry winter rest from the time vines die back until new buds emerge in spring.

What hayata's stephania's hardiness rating actually means

Hayata's Stephania 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 — 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). Hayata's Stephania has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Hayata's Stephania hardiness — frequently asked questions

Is hayata's stephania cold hardy?

Hayata's Stephania 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. Hayata's Stephania can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature hayata's stephania can survive?

What hardiness zone is hayata's stephania?

Hayata's Stephania is rated USDA 10-12 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can hayata's stephania 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 hayata's stephania 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.