Wash the rose hips and remove the stems and the dried part on top.
Measure 5 cups of rose hips, then add to a clean pot. Add the orange slices and cover with 4 cups of water. Bring the mixture to a boil, then simmer for 15 minutes.
Mash the rosehips during the last 5 minutes of cooking to extract their juices. Strain through a strainer, set over a large measuring cup. Reserve the rosehips.
Pour the strained liquid through a soup bag to clarify it even further.
While the rosehip juice is straining, add the reserved rosehips back into the same pot and cover with 2 cups of cold water. Bring back to a boil and simmer for 15 minutes.
Repeat the straining process, first through a strainer, then through a soup bag.
For every 1 cup of juice, add ½ cup of sugar. I had 3 cups of juice, so I used 1½ cups of sugar.
Add the rosehip juice, sugar, and rose flower water to a clean pot. Stir over medium heat until the sugar dissolves.
Bring the mixture to a boil, then simmer for 5 minutes. Skim foam if necessary.
Cool the syrup slightly before pouring it into a 16-ounce bottle. Store the bottle in the refrigerator and consume it within 6 months.