Twisting vines cannot be placed in flowed pots, these are different from Weeping Vines as those start growing from the top of a block but twisting vines do start growing from the bottom of a block so there is no reason that these can’t be placed in flower pots. Hopefully I didn’t make your mind a mess, I’m not a native speaker.

TLDR: Twisting Vines can’t be placed on a flower pot although these do start growing from the bottom of a block and not the top.