Oxalis stricta (sourgrass, lemon clover, sheep sorrel, common yellow oxalis)

description:  summer annual

place of origin:  North America and Eurasia

urban habitat: commonly found in vacant lots, pavement openings, rubble dumps, roadsides, highway medians, drainage ditches, and in neglected ornamental landscapes; thrives in nutrient-rich soil but tolerates both shade and drought.

ecological function: disturbance-adapted colonizer of bare ground; habitat for insects.

history: Although native to eastern North America, Oxalis stricta is commonly considered to be a weed of gardens and lawns. The Iriquois used an infusion of the plant to treat fevers, cramps, nausea, as a mouth rinse, and used a decoction of its roots as a blood medicine. The Iriquois also used a compound made from the plant ceremoniously. The Omaha used a poultice of the plant to treat swellings. The plant was consumed widely by the people of several Native American tribes and used as forage to feed horses. All parts of the plant are edible with a distinct bitter flavor due to its oxalic acid content, and is often consumed raw as addition to salads. A lemon-flavored drink can be made from its leaves and drank brewed as an herbal tea. The juice of the plant has been used as a substitute for vinegar. A yellow/orange dye can be made by boiling the whole plant.

Georgetown University Urban Herbs