Green Tea Leaf farming
I made this Green Tea Leaf farming guide to help out players who want to farm the herbs instead of buying them from the Auction House. You can pick this Herb from skill 1, but you will only get [Torn Green Tea Leaf] until you reach Herbalism skill 450-500 (10 makes one herb). Keep in mind you will not have access to flying mounts until you reach level 90, so you won't farm Geen Tea Leaf that efficiently before you reach level 90.
Green Tea Leaf
Jade Forest is the best place to farm Green Tea Leaf. I have two routes that I usually use, depending on how many players are farming in the zone. If you are the only one in the zone, then I recommend using the first route.
Valley of the Four Winds
Valley of the Four Winds is also a great place to farm this herb. The red route is called Skyrange, but you can only access if if you have a flying mount, it's usually worth it to do a lap there while you farm in this zone.