For the woodruff extract, bring sugar and water to a boil. Remove from heat, add 1 bunch of woodruff and leave to infuse for 10 minutes.
Pour the syrup through a hair sieve. If desired, add some ready-made green woodruff syrup to make the green color more intense. Pour the woodruff extract into a carefully cleaned bottle and close tightly. Store in a cool, dark place and consume within four weeks.