This species is native to South America, but it has naturalized throughout the southeastern United States. The magenta-purple flowers bloom continuously all summer long.
Verbena rigida is a spreading perennial in zones 6-9. Grow it as a self-sowing annual in colder zones. It makes a good groundcover because it can colonize large areas. It may be considered invasive. I grow it around large shrubs.
Also known as Tuberous or Tuber Vervain, Stiff Vervain, and Verbena venosa.