I made this Dreamleaf 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, you will get the same number of herbs as if you had Herbalism 100.
One of the new features in World of Warcraft Legion is that herbs have ranks now. You can get the new ranks from quest items that you get by picking [Dreamleaf]. Once you finish the quest you get from the herb and the follow up quest, you will get the new rank.
- Rank 1 : Gather dreamleaf more effectively.
- Rank 2 : You can get [Blood of Sargeras] when gathering dreamleaf.
- Rank 3 : Gather even more materials from each dreamleaf plant.
Dreamleaf
Get these three items to speed up farming: [Leystone Hoofplates], [Demonsteel Stirrups], [Stonehide Leather Barding].
If you have the 
[Sky Golem] mount, you can use that instead of the Demonsteel Stirrups, and if your class has a tanking spec, you should switch to that while farming, so you won't get dazed and you don't have to use Stonehide Leather Barding.
Don't forget to enchant your gloves with 
[Enchant Gloves - Legion Herbalism]! This enchant brings gathering time down from 1.5 seconds to 0.5 seconds. This is really important if you gather while mounted, because mobs can still interrupt your casting.
Val'sharah - killing mobs
The best way to farm Dreamleaf is to kill Vilepetal Rooters and gather herbs from their corpse. You can also gather Dreamleaf from the corpses of Defiled Grovewalkers but the drop rate is a lot lower.
Val'sharah - gathering herbs
Sometimes a Nightmare Creeper will spawn when you pick this herbs, and you should always kill them since they drop 7-11 Dreamleaf.
This route is for players without flying mount. (If you barely find any herb, it means someone is already farming there.)
If you have flying mount and use the recommended enchants above, you might farm too fast and you need to take a bigger loop around the zone to allow the herbs to respawn. So use this map below:
