Ivy used kryptonite when she mutated her newest plants

A green vine wraps around Supergirl’s leg, which should be no problem for someone as powerful as her, but when she tries to pull away she can’t....and she’s starting to feel weaker. “What the hell is this?!” Supergirl asks, though she already knows the answer. “I collected a sample of kryptonite from a wealthy benefactor in Metropolis that I’m sure you’ve heard with the promise of turning you over to him if I ever captured you.”

“Well that’s not happening!” Batgirl yells, throwing her batarang toward the vine and cutting it so Supergirl is free from its clutches. The effort is futile, for the moment Supergirl is freed from the first vine several more swarm her and grab her as Ivy uses her powers against her. “Batgirl, do something!” Supergirl yells, frantically.

Batgirl runs toward Poison Ivy to attack her, but Harley Quinn hits her in the back of the head with a giant mallet. Batgirl falls the ground, her vision filled with stars as she recovers from that blow. While Batgirl is temporarily unable to do anything, vines start to wrap around her too, and by the time she is able to realize what is happening she is already subdued. And just like that both heroines have been captured.