Arrowweed

Pluchea sericea, commonly called arrowweed or cachanilla (Mexico), is a rhizomatous evergreen shrub of riparian areas in the lower Sonoran Desert and surrounding areas. It is common in the lower Colorado River valley of California, Nevada and Arizona, as far east as Texas, and in northern Mexico where it often forms dense impenetrable thickets. It is a perennial shrub and grows along watercourses.