Actually, Plant has excellent synergy with Psi. Hit seeds of confusion, run into the middle of the throng of foes as they clump up to attack each other. Hit the AOE immob and PSW. Also, a Domination fueled Seeds of Confusion has been a great tool with all the custom mobs in AE resisting stuns and holds. They don't seem quite so resiliant against confusion.
Obviously, in the early game, you can use the Seeds then Psy Scream since the two cones match up pretty well.