Stachytarpheta jamaicensis

Stachytarpheta jamaicensis is a species of plant in the family Verbenaceae, native throughout the Caribbean, including Florida. It has many common names including blue porterweed, blue snake weed, bastard vervain, Brazilian tea, Jamaica vervain, light-blue snakeweed, and, in St. Croix, worryvine.source? It usually is found along country roadsides, and it also grows well as a ruderal plant on disturbed terrain. A similar plant, Stachytarpheta cayennensis, which is an invasive species in Florida, is sometimes mistaken for S. jamaicensis. It is unclear whether S. indica is a separate species.

from Wikipedia