Did you read the sulien list I posted? I mentioned two spots in that thread that you can gather from. Both require a "Blasted Oak Staff" (NA Localized Name from what I've been seeing). In the main Sulien Ecology area the spots there give mostly herbs when you gather from them which can be poison, bloody, base, mana, sunlight, or garbage (maybe others) and have a rare chance of getting sulien fragments.
There's an NPC in there who will teleport you deeper in where there's areas with mobs. Inside there you will find some "glowy" spots that don't sparkle as much but look more like a glowing orb (easier if you just see the pictures in the thread I made about it). Those spots will have a much higher chance of getting sulien fragments instead of herbs but you can still get herbs from them at a relatively decent rate.
Each time you gather you will consume MP and of course the dura of the staff. Does that help any?
Fragment of Sulien/Sulien Fragment/Sulien Crystal - Obtained from spots that look like this:
Higher chance
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[Image: http://i228.photobucket.com/albums/ee199/kingofrunes/ecology_gather_zps4fc58ce3.png]
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Much lower chance (higher chance of herbs: poison,bloody,mana,base)
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[Image: http://i228.photobucket.com/albums/ee199/kingofrunes/herb_gather_only_zps520b0ee7.png]
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