On a beautiful day in the morning, pick the dog rose and elderflower in a place that is as unpolluted as possible and spread it out briefly on the balcony or garden table so that insects can crawl away. Do not wash the flowers.
Measure the rose petals in a liter and press them together a little. Pour the water into a saucepan, bring to the boil and simmer on a medium flame for about 10 minutes.
Add the citric acid, the sliced lemon and the elderflower to the cooled water. The flowers should be cut off just behind the stems so that there are as few green stems as possible.
Cover the pot and let it steep for 2 days in a cool place. Stir every now and then.
Pour the liquid through a sieve. Add the sugar, bring to the boil and season to taste. If the rose taste is not dominant enough for you, you can add a dash of rose water.