Russian Olive - (Elaeagnus angustifolia L.) - was introduced into North America in the late 19th century, and subsequently escaped cultivation because its fruits are relished by birds which disperse the seeds. Russian-olive is considered to be an invasive species in many places in the United States because it thrives on poor soil, has low seedling mortality rates, matures in a few years, and out competes wild native vegetation. It often invades river or stream banks where cottonwoods have died.