S1·E25 Garden of Evil

When Swamp Thing has a blind date with Poison Ivy which leads to her controlling him in her plot to overrun Gotham City with plants, Batman works on an antidote to free Swamp Thing from Poison Ivy's control. Meanwhile, Poison Ivy is collaborating with Harley Quinn to help her keep Swamp Thing in check. So Superman, Firestorm, and Vixen work to fight Poison Ivy and Harley Quinn on their home turf.