Pamela Lillian Isley first appeared in Batman #181 in 1966. Like Athena she appeared fully formed and without a back story. Showing up in basically a leafy swimsuit, tights(character design by Shelly Moldoff) and very little story she failed to catch on first go around.
Unable to capture the public's imagination in #181 Poison Ivy was shelved (if you don't count Siren played by Joan Collins on The Batman TV show) until feminism began to saturate the public and the need for more independent, beholding to no man, women were needed. Be they superhero or villain. Especially since Catwoman was becoming more and more sympathetic to readers and less a villain. On her reintroduction she appeared in Batman Comics and Suicide Squad. With all these manifestations a true origin was needed for Ivy.
She was now Dr. Pamela Isley, a brilliant botanist. Until the Floronic Man (aka Dr. Jason Woodrue) showed up in her life. Experimenting upon her, trying to hybridize plants and humans, he pumped her blood full of toxins. With those experiments she became immune to all poisons, viruses, bacteria, and fungi and just a touch bit insane. The experimentation also left her unable to mother children and plants became her substitute for the children she could never have. In one of these early stories during a fight with Catwoman one of Ivy's own formulas fell on her, turning her skin green. The transformation from Dr. Pamela Isley to Poison Ivy was now complete. One of Ivy's chief new powers was the ability to control plants telepathically.
Another nifty ability she uses is being able to release plant pheremones to control men or women and making them fall madly in love with her. One of her favourite powers is releasing either toxins or pheremones through her kisses.
Coming out of Batman: The Animated Series (Writing, Paul Dini, artist/character design Bruce Timm) is her friendship with Harley Quinn (aka Dr. Harlene Quinzel). Wanting only to get Harley out of her abusive, destructive relationship with The Joker, Harley and Ivy team-up from time to time.
The most recent change to her character was during Batman: Cataclysm storyline where Ivy took care of some children, recently orphaned during the earthquake that nearly leveled Gotham City. She began to believe that her powers and the poisons she gave off were sickening and killing some of the children in her charge. For this reason she convinced Batman to take her powers away and make her only human again. Later convinced by the villain Hush to retake the serum to reaquire her powers the process apparently killed her. When her grave was visited it was covered in ivy and vines making her 'death' short lived.
She returned in Gotham Central #32 to murder some of the cops she reckoned killed one of her orphans.
Poison Ivy is one of my favourite Batman villains because she believes what she's doing is right. Not like some of the mustache twirlers who just do evil for evil's sake and wish to take over the world. Her next main appearance is during Battle for the Cowl in Gotham City Sirens, co-starring Catwoman and Harley Quinn. I really dig Dini's take on all these characters and I reckon it's going to be the best out of the bunch along with Detective Comics starring Batwoman. So, fingers crossed that it's as good as I hope.
Below are some of my favourite Poison Ivy pics. Please click to embiggen.