If Bruce Wayne is who Poison Ivy wants to convince to help in her quest to “save the planet,” why doesn’t she try to seduce him away from his girlfriend with her love dust and sexual charms to make him do her bidding?
A cut scene actually had this happen at the event late in the film when Bruce was with Julie, and she broke up with him after he accepted to go on a date with her, but it didn't happen. He was quite resistant to it while doing his job as Batman, but not so much as Bruce Wayne. This is what causes Bruce to take a closer look into Pamela Isely and discover that she really is Ivy. There was also a line not in the final film from the script where Ivy asked if he would attend the charity event over Julie after she first met him with her proposal. My take on it is that she couldn't rely on seducing him so easily as long as Julie was standing in the way.