What my grandmother used to call, with a disdainful sniff, "hedge." Native to China, introduced to the U.S. as an ornamental plant. Escaped cultivation in the 1930s or so, now hugely invasive, grows everywhere, displaces native plants, masses along highways. Flowers have an acrid, bitter smell. Can grow large enough to have an actual trunk.
Included by Mississippi State University in the list of "Mississippi's Top 10 Invasive Weeds." From www.msucares.com:
Introduced in the United States as an ornamental shrub in 1852. Found throughout the South, Chinese privet forms dense thickets along roadsides, fence rows, fields, rights-of-way, and in forested creek bottoms. These shrubs typically reach 10 to 20 feet in height with numerous branches. A member of the olive family, privet produces seeds abundantly and regenerates by root sprouts quickly forming dense stands. Because of dense stand production, privet crowds out native plants and trees, especially hardwoods. Privet typically produces small white flowers in early summer and terminal clusters of seeds in the fall. Seeds are consumed primarily by birds and disseminated.