Petal Dance, if you're running Own Tempo Lilligant. Energy Ball is better with her other abilities.
Petal Dance allows Lilligant to hit really hard and get rewarded by removing the confusion penalty with Own Tempo. A special 180 base power move that hits 3 times without a drawback can be really devastating for the opponent (STAB + Base Power). Quiver Dance boosts can make it even more terrifying. Own Tempo isn't a hidden ability, so it's more accessible and more useful. However, it's a little bit more gimmicky than energy ball.
Energy Ball is better on Chlorophyll and Leaf Guard, because Petal Dance would confuse Lilligant. 90 Base power with a chance to lower special defense, it can be quite good. Hitting hard with a chance to be able to hit even more harder the next turn is great for Lilligant.
I would recommend Petal Dance, because it can be really powerful. Own Tempo Lilligant isn't very hard to get, so this setup is really easy to use.
