I ended up adapting syrup recipes from The Spruce Eats and Susan Can Cook. I had about ¼ cup of trimmed rose hips, so I added ¼ cup of water in a saucepan and brought it to a simmer. However, the water evaporated too quickly, despite the lid on the saucepan, so I ended up mashing the rose hips a bit (they were too hard for me to cut them open and remove the innards) and adding another ¼ cup of water, boiling it a bit and then letting the whole thing steep. I strained the mixture and ended up with 6 tablespoons of rose hip water, so I added 3 tablespoons of sugar, boiled the mixture long enough for the sugar to dissolve, then kept the syrup in the fridge.
I used it in drinks, mostly mixing it with ginger ale. I could definitely taste the syrup, and it was pleasant, but it’s very hard to describe that taste! Even when I tasted it on its own, the syrup didn’t have the taste I expected – to be fair, though, I’m thinking of the smell I associate with rose hips, and they may not necessarily taste quite like that.
To be honest, I’m not sure that I’ll bother making it again, at least not with so few rose hips, but I’m glad I made something with them for once.