Probably originally native only in southern Europe, but now a widespread naturalized weed. Roadsides, railroads, fields, parking lots, and other disturbed sites; a weed in lawns, gardens, and nurseries. The earliest Michigan collection seen is from Ann Arbor (Washtenaw Co.) in 1860; apparently collected soon afterwards in Flint (but specimen undated); well established across the state by the 1890’s.