In a medium (3-quart) stainless or enameled saucepan, bring 1 1/2 quarts of water to a boil. Add the "flowers" and sugar. Stir for a minute or so, while the liquid returns to a boil and the sugar dissolves. Cover and let steep for at least an hour, but no more than 2.
Pour the mixture through colander or strainer into a large bowl, pressing on the "flowers" to extract as much liquid as possible. Stir in 3 cups water.
This recipe makes a tart version of auga de jamaica; feel free to stir in more sugar, if that appeals to you. Store covered in the refrigerator in a noncorrosive container (preferably one that won't stain).