Give me that fckkng flower please
Blue rose Corolla

You can have them obtained through the Gift Shop NPC, which can be seen in almost every town within the game. On the other hand, if your Character is strong enough to kill some monsters in Chaos South Valencia(recommended CP: 13,500), you can obtain Blue Rose Corolla easier there. You can obtain the item named "Chaos Loot Chest". These chests when opened will give you with some Elion's Traces Chest, when used, it would give you some Gift Items including the Blue Rose Corolla. Also, they reduced the amount of Blue Rose Corolla that you will be needing if you're attempting to finish the For Siani Quest from 150 to 50. So it should be easier to have it finished.