UK hardiness
Is Bertolonia maculata hardy in the UK?
Bertolonia maculata
More about bertolonia maculata in the UK
Bertolonia maculata and the RHS hardiness rating
Bertolonia maculata is rated RHS H1a — heated glasshouse — tropical, meaning it withstands winter minimums of about above 15°C. In practice that means it cannot live outdoors in the UK at any time; a warm indoor room or heated glasshouse only. 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 bertolonia maculata USDA hardiness guide.
Does UK region change it?
Because bertolonia maculata 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 bertolonia maculata in the UK
Overwintering bertolonia maculata 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.
Bertolonia maculata UK hardiness — frequently asked questions
Is bertolonia maculata hardy in the UK?
Bertolonia maculata is rated RHS H1a (heated glasshouse — tropical, hardy to about above 15°C). It is not winter-hardy anywhere in the UK and must be overwintered under cover.
Can bertolonia maculata stay outside over winter in the UK?
No. Bertolonia maculata is frost-tender — a UK frost will kill it. Bring it indoors or into a frost-free greenhouse before the first autumn frost and return it outside only after the last spring frost.
What does RHS H1a mean?
RHS hardiness ratings run H1a (needs a heated glasshouse) to H7 (survives below -20°C). Bertolonia maculata's rating, H1a, means heated glasshouse — tropical — it tolerates winter minimums of about above 15°C. The rating is an absolute minimum, not an average.
How do I overwinter bertolonia maculata in the UK?
Overwintering bertolonia maculata 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.
Does UK region change whether bertolonia maculata survives?
Because bertolonia maculata 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.
More bertolonia maculata care
See the full bertolonia maculata care guide, its temperature & humidity needs, and the US (USDA) hardiness version of this page.