Return to the Botanical Gardens--Part 1

Inside the Botanical Gardens, you'll find the main route is still blocked off. No sweat--hop into the alcove and vent on the left and follow it to a hole in the ceiling that can be grappled up. Now proceed through the Gardens until you find Poison Ivy--the path is really straight forward; in fact, one of her slithering tentacles will lead you right to her.

Hmm Poison Ivy doesn't look so attractive now, does she? Anyway, despite her menacing appearance, she's quite a push over. Simply run back and forth along the platform, rolling to dodge her attacks, and fling quick-Batarangs all the while. After inflicting some damage, the head will drop to the ground, allowing you to plant some explosive gel on her cocoon. Afterward, you'll have to repeat the sequence once more, but this time you'll be attacked by some inmates as well. It's best to simply ignore them (by rolling over them) and focus on tossing Batarangs at Ivy. Before long, her head will drop once more allowing you to plant one more gel explosive, taking her down for good.