WARNING: The following article contains major spoilers for Heroes in Crisis #9 by Tom King, Clay Mann, Tomeu Morey and Clayton Cowles, on sale now.
Heroes in Crisis introduced the concept of Sanctuary, a facility where superheroes and supervillains could deal with their emotional traumas. Harley Quinn served as one of the series' focal characters, but she wasn't the only Bat-villain who checked in. Poison Ivy joined Harley at Sanctuary after briefly taking over the world in the Batman arc "Everyone Loves Ivy." Unfortunately, Ivy was one of the victims of the Sanctuary massacre. The good news is, her demise wasn't permanent, and her journey back to life is explained in Heroes in Crisis #9.
What Happened to the Old Ivy
The Sanctuary massacre was the result of an emotional overload suffered by Wally West, aka The Flash, as learned via flashback in issue #8. Wally became emotionally overwhelmed after poking around in Sanctuary's data files and learning of his fellow superheroes' own traumas. When others tried to aid him, the distressed Wally lost control of his powers, momentarily unleashing the energies of the Speed Force in their presence. All those in his proximity were killed instantly – including Ivy, who was closest to him when he lost control.
While the massacre occurred prior to the events of Heroes in Crisis #1, Ivy's death wasn't revealed until the following issue. In that chapter, Harley was seen tossing a rose off a bridge, in memory of her slain partner. In issue #5, that rose washed ashore and was found by an unknown figure – now known to be Wally.
Wally knew to retrieve that rose because, as shown in issue #8, his future self told him to. That is, Wally from five days after the massacre, who went back in time to confront himself at the scene. Future Wally also instructed his past self to plant the flower at the same location, before past Wally commits the pseudo-suicidal move of killing his future self. In the previous issue, Wally did indeed return to the scene and plant the now-wilted flower, giving it a small life-restoring jolt of energy from the Speed Force.
What Happens to the New Ivy
That rose, given to Harley as a Token of Ivy's affection, wasn't just any ordinary flower, though. As Ivy reveals to Harley in issue #9, that rose was actually a part of her. Once planted and brought back to life, the flower grows into a large incubating pod, from which a newly reborn and significantly altered Ivy emerges, as shown shortly after Wally planted the rose in issue #7. What the Speed Force takes, it also apparently gives back.
In issue #9, Ivy reveals her essence had merged with The Green – the elemental force for plant life, as previously seen in Swamp Thing and elsewhere. Ivy also adds that she changed The Green, although exactly how isn't known. No longer Poison Ivy, she's seemingly now another avatar of The Green, not unlike Swamp Thing – only she just might also have a touch of the Speed Force within her.
This isn't Ivy's first contact with elemental forces. She played a part in the "Rotworld Saga" – the Swamp Thing/Animal Man crossover event from 2012. Her involvement with these forces goes back even further than that: She was featured in Neil Gaiman and Dave McKean's Black Orchid series some three decades ago. In that series, Swamp Thing himself identified Poison Ivy as having elemental influence. And she's been shown to have connections to The Green periodically in between.
The Ivy to come out of Heroes in Crisis therefore seems to be a natural evolution of the character – and potentially elevates her into something immensely more powerful. The still unseen alterations to The Green might also prove to reveal themselves elsewhere in the DC Universe. If Ivy returns to a world of true villainy, Batman might have himself a brand-new set of challenges.