"This is an ancient herb, said to have been used by the soldiers of Troy to treat battle. The druids would use yarrow in meteorology and the Chinese still use it to foretell the future (I Ching).  An old world spell which is said to reveal one’s true love goes : "
Good morning, good morning, good Yarrow
And thrice a good morning to thee;
Tell me this time to-morrow,
Who my true love is to be.