I've been harvesting these pretty regularly in Grauberg (S) as I farm. So far I've gotten about 2 stacks total and have npc'd some of them and am trying to sell the first stack ever in AH. I haven't attempted eating one outright, even if it is possible. Perhaps I'll eat one and see if I can notice anything to stats, regen, refresh, etc for effect. I hate to waste somethign that will at least sell for decent gil to npcs....but....meh.
Located in West Sarutabaruta {S} by harvesting. I got two in about 6 harvest spots along with moko grass, a skull locust, fresh marjoram, flax flower, herb seed, and veggie seed.