Yell0w

Hej community! I'm totally new so please forgive me if I did anything wrong I could not find an answer to this via google. If I use Barbaric Blow with Serafen (pure barbarian) I do not deal damage in an area. If I attack with a weapon attack I do deal damage in an area. I am using the "Spine of Thicket Green", a two-handed quarterstaff. Why does Barbaric blow not do Carnage damage in an area?