Rose de Berne tomato, the 1946 Swiss variety to grow outside
A round tomato with a thin skin, bred in 1946 near Bern. In a wet summer, it ripens outside with shelter and regular watering.
The Rose de Berne is a Swiss tomato, bred in 1946 by Werner Trojahn, a gardener at Bremgarten, near Bern. Round, carmine red, with a very thin skin, it is known for its taste. Outside, it needs shelter from rain and regular watering. Otherwise, its fruit splits.
Its history, found again by ProSpecieRara
For a long time, little was known about the Rose de Berne. The variety database TOMATObase even calls it French. In 2025, ProSpecieRara, the Swiss foundation that conserves heirloom varieties, did the archive work. Its magazine rara tells the story in issue 4 of 2025.
| Year | The event |
|---|---|
| 1946 | Werner Trojahn, who runs the Lindenweg nursery with his wife Rosa at Bremgarten, breeds the variety and registers it under the name Rose de Berne |
| 1948 | The catalogue of the seed company Haubensak announces it: "original seed, novelty, large carmine-red tomato, very fleshy" |
| 1950s | The couple separate, the nursery goes bankrupt. The seeds, Rose de Berne included, pass to the horticultural firm Rudolf Roggli |
| 1952 | Haubensak entrusts seeds to the German gene bank at Gatersleben. Roggli later entrusts some to the Dutch gene bank |
| 2002 | ProSpecieRara receives seeds from a seed grower, without knowing their origin |
| 2025 | Michelle Preiswerk, tomato specialist at ProSpecieRara, finds the breeder's son and organises a tasting |
The name keeps some mystery. Rosa was the first name of Werner Trojahn's wife. It was also the name of his mother-in-law. Does the name of the variety come from them? Even Christian Trojahn, Werner's son, does not know.
The 2025 tasting
A variety kept in several places changes over time. Climate, gardeners' selection and small natural variations give different lines. Many said the Rose de Berne had lost its character.
So ten lines grew side by side in the show greenhouse of the Reusspark, in Switzerland. Christian Trojahn and his wife Ursula tasted them one by one. "That is not my Rose de Berne," he said more than once. After two hours, three lines were kept, close to the original according to the breeder's son. They are those of Roggli, of Haubensak and of ProSpecieRara. The line closest to the tomatoes in a photo from the 1940s came last on taste.
Its taste and its look
The three lines kept have the traits that tradition gives the variety. In the mouth, it leaves a very pleasant feel and a light acidity, refreshing at the end of the bite. The aroma is pronounced, the skin very tender. For Ursula Trojahn, the acidity should be felt in the throat, not on the roof of the mouth.
In the 1940s photo, you recognise a raspberry colour, a round shape and long sepals. Christian Trojahn ate it on a piece of bread, with no salt or oil.
| According to the sources | |
|---|---|
| Fruit | Round, carmine pink, about 7 cm and 150 g (Sativa); about 200 g (Plantura) |
| Skin | Very thin, hence fruit that splits easily |
| Plant | Indeterminate growth, up to 2 m (Plantura), needs staking |
| Earliness | Mid-late (Sativa); first ripe fruit from early August (Plantura) |
| Needs | Warmth and high nutrients (Sativa) |
Growing it outside
Sativa, the Swiss seed company that multiplies it, rather advises growing it under cover. Outside, it strongly recommends shelter from rain. Plantura calls it fairly sensitive, especially to rain. The site gladly puts it against a warm, sheltered wall. In a wet summer, it is therefore a tomato to look after.
The calendar follows that of all tomatoes, detailed in the full tomato season. In Switzerland, ProSpecieRara sows from mid-March. The plants only go out after the Ice Saints, in mid-May. On the Belgian plain, keep the same landmark. Wait for the Ice Saints, or for minimums above 5 °C over seven days.
And blight, compared with the Triomphe de Liège?
We found no figures from a blight trial for the Rose de Berne. Nor for the Triomphe de Liège. Its sheets contradict each other, between decent resistance and great susceptibility, as its portrait details.
| Rose de Berne | Triomphe de Liège | |
|---|---|---|
| Documented origin | Switzerland, 1946, Werner Trojahn | Belgium, 1903 according to seed company sheets, no document from the time |
| Sources' advice for outdoors | Shelter from rain strongly recommended (Sativa) | Contradictory views on blight |
| Blight trial result | None found | None found |
| The move | Shelter, spaced plants, water at the base | Same, treating it as a susceptible one |
So the caution holds for both. Space the plants, water only at the base and put up a shelter if you have one. The criteria that predict blight are in the article on tomato blight.
Where to find its seeds
The Rose de Berne is not in our catalogue. Sativa offers it as seeds and as plants, under the ProSpecieRara label. It is a fixed variety. You can therefore keep your own seeds from year to year, with the fermentation method. Your garden then becomes one more place where the variety is kept.
For an heirloom tomato with a local name, the Triomphe de Liège is in our catalogue, with our other tomatoes in the Tomate Lovers collection. To follow your tomato sowings with the dates for your garden, the app takes care of it.
FAQ
Is the Rose de Berne an heirloom tomato?
Yes. It was bred in 1946 and ProSpecieRara has conserved it since 2002. It is a fixed variety. Its seeds give the same tomato again.
Can you grow it outside in Belgium?
Yes, with shelter from rain if possible, as Sativa recommends. Plant it after the Ice Saints against a warm wall and water regularly.
Why do my Rose de Berne split?
Its skin is very thin. Irregular watering or heavy rain after a dry spell makes the fruit swell too fast. Keep the soil evenly moist and mulch.
How much does the fruit weigh?
About 150 g for Sativa, around 200 g for Plantura. On TOMATObase, the gardeners who describe it give weights that vary from year to year.
Photo: Frank C. Müller, Wikimedia Commons, licence CC BY-SA 4.0
Sources
- ProSpecieRara, magazine rara n° 4/2025, Que se passe-t-il avec la ’Rose de Berne’ ? (Simone Krüsi : création en 1946 par Werner Trojahn, catalogue Haubensak de 1948, dégustation de dix lignées au Reusspark)
- Sativa Rheinau, fiche Bernese Rose (150 g, 7 cm, rose carmin, mi-tardive, culture sous abri conseillée, abri contre la pluie dehors)
- Plantura, Berner Rose tomato: cultivation and plant care (environ 200 g, jusqu'à 2 m, sensible à la pluie, éclatement et cul noir si l'arrosage varie, maturité dès début août)
- Tatiana's TOMATObase, Rose De Berne (indéterminée, rose, mi-saison, avis de jardiniers sur le goût et le poids)
- ProSpecieRara et Tomates urbaines, Guide étape par étape Tomates (semis dès la mi-mars, plantation après les Saints de Glace, emplacement protégé de la pluie)
- RHS, Tomatoes: fruit splitting and cracking (variations d'humidité du sol et de température)
He gardens in Belgium and tries out in his own vegetable patch what the app recommends. His articles always start from a source you can check and a step you can take this weekend.
