  Yarrow is a wispy yellow flower related to Dandelions.
<~><~>  They are found in Ancient Forests and Ancient Hills growing among the Oaks and Clovers. 
<~><~>  Yarrow is connected to Aeromancy magic. Though it is most useful when it is dried and crushed.
<~><~>  Yarrow Seeds can be grown on Farmland. Their seeds can be crafted by putting Yarrow in a crafting table.
<~><~>  Yarrow can also be crafted into Yellow Dye in a Mortar and Pestle.