Alfalfa also called lucerne and called Medicago sativa in binomial nomenclature, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world.Alfalfa is considered a “superfood” because it's loaded with the vitamins your body needs to generate new cells and boost your immune system. Its deep roots allow it to soak up tons of vitamins while it's growing.