Can't Use Nutrition Potion on Withered Vine

[creativeschema]

I talked to Rubrum (several times) about the withered branch and I've made the nutrition potion but it doesn't give me an option to throw it. If I examine the vine, Ellie and Virgil just talk about it like I can ask around, but nothing happens after that (no new quests or anything). I have no idea what to try to fix this problem.

[The Queen Salis]

you need to use the in-game throwing mechanic to aim and throw in most situations

[creativeschema]

that was it, thanks. I thought the throw mechanic was automatic -- think this was the first time I had to pull it up myself