BTW Lucy Broadwood stated that "Both abroad and in the British Isles one meets still with so many instances of plants being used as charms against demons,that I venture to suggest that these "plant-burdens", otherwise so nonsensical, are the survival of an incantation used against the demon suitor..........
.....from earliest times, the herbs or symbols efficacious against the evil eye and spirits, are also invariably used on the graves of the dead, or during the laying of the dead to rest"
Her analysis of the plantlore in the above ballads is based upon Friend's "Flowers and Flower Lore" -

Rosemary, called Alicrum or "Elfin Plant" in Spain and Portugal is worn there against the evil eye and burnt against witches in Devonshire