Is Hoya Pubicalyx 'Black Dragon' hardy in the UK?

Hoya Pubicalyx 'Black Dragon' and the RHS hardiness rating

Hoya Pubicalyx 'Black Dragon' is rated RHS H1b — heated glasshouse — subtropical, meaning it withstands winter minimums of about 10 to 15°C. In practice that means it indoors over winter; can summer outdoors once nights are reliably mild. The RHS rating describes an absolute minimum temperature, not an average: a single hard frost below its band is what does the damage, so the question is always "what is the coldest night my garden gets?", not "what is a typical winter here?".

This follows the RHS plant hardiness rating system (H1a–H7), the UK standard. For the US growing-zone view, see the hoya pubicalyx 'black dragon' USDA hardiness guide.

Does UK region change it?

Because hoya pubicalyx 'black dragon' is frost-tender, UK region matters less than the simple rule: it does not stay outdoors over winter anywhere in the UK. Treat any time outside as a summer holiday — bring it back indoors once nights drop toward 10°C, well before the first frost, and acclimatise it over a week each way so the leaves do not shock.

Overwintering hoya pubicalyx 'black dragon' in the UK

Overwintering hoya pubicalyx 'black dragon' in the UK means bringing it in: a bright, frost-free room or a heated glasshouse, watered sparingly while growth slows. Do not leave it against cold glass or near an unheated porch. Move it back out only after the last spring frost has passed for your area.

More hoya pubicalyx 'black dragon' care

See the full hoya pubicalyx 'black dragon' care guide, its temperature & humidity needs, and the US (USDA) hardiness version of this page.

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