Swamp Flowers are the items required for the quest To Dye For.
Swamp Flowers are located all over Zehlon Reach, including near the locations of Shaudok and Kohanu. The easiest Swamp Flower plant to find is just north of Jokanur Diggings. Go past the resurrection shrine and down to the water.
You only need to pick up one Swamp Flower to complete the quest.
You can pick the same flower an infinite amount of times, each adding one flower to your inventory.