Parsley
Parsley is a plant associated with death, the dead, and Ghosts. The ancient Greeks and Romans considered parsley to be sacred to the dead and placed it on graves. In the Celtic world, parsley acquired a reputation for bad luck due to its association with the dead: in the lore of Devon, England, for example, it is considered unlucky to transplant it, for that would cause a death in the family and the devil would take control of the garden. It is also most unlucky to be given parsley. Parsley also is a folklore remedy for those who are unfortunate enough to witness the spectral Wild Hunt, which results in blinding, swelling of the head and even death. All one need do is ask one of the ghosts for a bit of parsley.
The Encyclopedia of Ghosts and Spirits– Written by Rosemary Ellen Guiley – September 1, 2007