Medicago sativa
From Nearctica
Alien: Native of Europe.
Identification: Flowers usually blue or violet, although sometimes pink-purple. Flowers small, in clusters on long flower stems. Seedpods coiled. Leaves with 3 leaflets, each leaflet elongate and narrow. Plant 1 to 1.5 feet in height.
Distribution: Throughout North America.
Habitat: Alfalfa is a cultivated plant and commonly escapes to roadsides, fields, and other disturbed habitats.
Flowering period: May to October.