On this page of our game guide to Batman: Arkham Knight you can find a description which explains how to protect Poison Ivy's plant from enemy military forces. Also, you will find some tips on defeating a new large group of bandits.
Another compulsory battle awaits you, this time you have to eliminate all the opponents on the rooftop of a building near to Batman's current position. If possible, it is best to take them out by surprise, the more that you do not have to hurry with this. First of all, try eliminating the enemy medic to prevent him from electrifying the armors of his friends. Beware of the heavy soldier, whom you can defeat using Beatdown skill. When you win the battle conversations with Poison Ivy and Alfred will start.