Poison Ivy's Plants were venomous plants in Batman: Arkham Asylum. They were capable of killing people directly with their vines, or indirectly by sending out poisonous spores.
Before Arkham Asylum Incident
Ivy created plant pods that released deadly spores that sought out anything that moved. She used these to attack Gotham, before Batman managed to stop her and send her back to Arkham.
Arkham Asylum Incident
Following Ivy getting an injection of Titan, it's effects worked differently on her; instead of her body mutating into a giant form, he plants grew rapidly. Multiple vines burst out of the ground on Arkham East, warpping around the lock tower. Another burst from the stairs in the Botanical Gardens.
As the night went on, Ivy forced her plants through the island, taking it over bit by bit. Anyone stupid enough to get close to them was killed by venus-flytraps attached to the vines, which swallowed their heads or bit off limbs. Some even broke into the Intensive Treatment Lobby's exit to the Utility Corridor while the Blackgate Prisoners were entering. Joker warned that prolonged exposure would shut down a person's nervous system.
Eventually, Ivy gained control of the entire island, using spores to make it glow red. Batman went back to the Botanical Gardens, which was now filled with Ivy's mutant plants. Ivy attempted to use a giant flower to attack him, but Batman damaged it, causing the plant to fall into a hole, along with Ivy. With Ivy out-cold all the plants on the island withered and died.
Arkham City IncidentSome plants could be seen growing in Ivy's old shop Baudelair, which ended up killing two thugs from Two-Face's gang.
Ivy herself resided in a hotel wrapped in vines to keep out intruders. Catwoman broke in, and Ivy attempted to use her plant spores to kill her. Ivy also kept her brainwashed muscle inside flytrap-like plants until she needed them.
Before Arkham Knight Incident
Harley Quinn used Ivy´s plants to takedown the Bludhaven Police Department Officers.