Garlic is a member of the allium family and forms a bulb. The bulb is segmented and forms cloves. The individual cloves in a head of garlic are planted as seeds. The cloves turn into bulbs that grow underground and produce edible leaves and stems and flowers.
Each clove will produce one plant with a single bulb - which may in turn contain up to twenty cloves for Jumbo Garlic and 4 cloves for Elephant Garlic. Growing garlic is therefore self-sustaining. Self-sustaining meaning . . . it produces its own from season to season.