Can confirm that it can be foraged from Rujarkian Hills: Blazing Forge. I did high-risk single boss group adventure requests until I got Noyon Ztun as the kill target. First forage in zone got me a potato.
More expansions, more eye candy, more nonsense. Meanwhile only those that own many accounts and box em all at once can do LDONS to get this one bloody item known as a Rujarkian Potato. SoE .... lost w/o a clue.