UK hardiness
Is Torenia fournieri 'Summer Wave Large Violet' hardy in the UK?
Torenia fournieri 'Summer Wave Large Violet'
More about torenia fournieri 'summer wave large violet' in the UK
Torenia fournieri 'Summer Wave Large Violet' and the RHS hardiness rating
Torenia fournieri 'Summer Wave Large Violet' is rated RHS H2 — tender, meaning it withstands winter minimums of about 1 to 5°C. In practice that means it needs a frost-free greenhouse or indoors over winter — a UK frost will kill it. 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 torenia fournieri 'summer wave large violet' USDA hardiness guide.
Does UK region change it?
Because torenia fournieri 'summer wave large violet' 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 torenia fournieri 'summer wave large violet' in the UK
Overwintering torenia fournieri 'summer wave large violet' 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.
Torenia fournieri 'Summer Wave Large Violet' UK hardiness — frequently asked questions
Is torenia fournieri 'summer wave large violet' hardy in the UK?
Torenia fournieri 'Summer Wave Large Violet' is rated RHS H2 (tender, hardy to about 1 to 5°C). It is not winter-hardy anywhere in the UK and must be overwintered under cover.
Can torenia fournieri 'summer wave large violet' stay outside over winter in the UK?
No. Torenia fournieri 'Summer Wave Large Violet' 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 H2 mean?
RHS hardiness ratings run H1a (needs a heated glasshouse) to H7 (survives below -20°C). Torenia fournieri 'Summer Wave Large Violet''s rating, H2, means tender — it tolerates winter minimums of about 1 to 5°C. The rating is an absolute minimum, not an average.
How do I overwinter torenia fournieri 'summer wave large violet' in the UK?
Overwintering torenia fournieri 'summer wave large violet' 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 torenia fournieri 'summer wave large violet' survives?
Because torenia fournieri 'summer wave large violet' 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 torenia fournieri 'summer wave large violet' care
See the full torenia fournieri 'summer wave large violet' care guide, its temperature & humidity needs, and the US (USDA) hardiness version of this page.