Basil

For luck, prosperity, solid relationships & clarity

Origins for witchcraft: Voodoo with their Goddess Ezili Freda Dahomey and India's Lakshmi.
Growth: Annual - best grown in warm weather, keep inside during the winter.
How it is used today: Brings wealth to those who carry it in their pockets. Also used for spells to make sure that your mate is remaining true - but remember: do not work anything against someone's will.  I personally would not do this, but some recommend that you sprinkle basil powder over your lover as they sleep to make sure that they remain faithful.  The put the oil in a burner for clarity, particularly where the mind is floating when you need to concentrate.
Properties: Antiseptic, antispasmodic, carminative, cephalic, digestive, emmengogue, febrifuge, nervine, tonic

Image from the Growing Basil Blog