Alfalfa is a perennial legume that usually lives for four to eight years, Alfalfa is a common plant across the Northeast, this plant is found in meadows, along rivers, in woodlands, and in abandoned fields. Alfalfa is a moderately sized shrub, this plants flowers are blueish white, the leaves of alfalfa are small and oval shaped. Alfalfa is used as a host by both clouded sulphur and orange sulphur caterpillars.