Wolfsbane seeds?

They're from Vampires, and can be found in the wild in Forgotten hollow

You need them for a couple of Mixology drinks related to vampires.

They are blue flowers, quite easy to spot and they are in season all year :)

Wolfsbane seeds are the seeds that wolfsbane plants grow from. You can order them from Vampire Secrets on the computer once your Vampiric Lore skill is high enough. You can also order them by clicking on garden planters.