Question is same as the title. How do you complete The Green Hills of Stranglethorn (World of Warcraft) quest once the zone has phased to level 85? NVM, I know now. You have to finish all the quests for level 85, leave the zone and come back. Everything resets once you do this.
You answered it yourself. The zone is phased only while the quests are active. Either complete them or abandon them and you can do whatever you want there.