I made this Astral Glory 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 800.
You should get [Stonehide Leather Barding] to avoid getting dazed. There are so many mobs at Argus, you simply can't avoid them while farming.
If your class has a tanking spec, you can switch to that while farming, so you won't get dazed and you don't have to use Stonehide Leather Barding.
[Demonsteel Stirrups] currently doesn't work at Argus.
If you have the [Sky Golem], you can use that to gather while mounted.
You should also 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, but with 0.5 second cast time, you can gather herbs even while 4-5 mobs are hitting you if you time it correctly.
This is the best place to farm, but there are a lot of mobs around the herbs in this zone, so make sure you get the enchants/items I recommend above!
You will only find Fel-Encrusted Herbs, but they drop Astral Glory.
Not much worse from Krokuun but I got fewer herbs/hour here.