Fennel

Fennel was currently used by the ancient because it was commonly known that it strongly repelled demons, ghosts and wizards as they couldn't stand the smell of it. So it was put into keyholes, in fireplaces, on doors and windows to keep out hermetically, psychic nuisance of any sort. Its effects are even stronger if it is put into place the morning of Saint John.

Its good reputation as a protecting plant is probably due to the fact that wherever it grows, the place is very sound, and emitting very good vibrations.