Verbena hastata, Blue Vervain is a rough, clump-forming 2 to 6 foot perennial that grows a tall stalk of flowers from summer to fall.  This is a wetland species of open habitats, but is easily grown in average, medium to wet soils in full sun. Flowers on each spike bloom bottom to top, only a few at a time, and are attractive to hummingbirds, butterflies, and other pollinators. Easily grown in average, medium to wet soils in full sun. Typically forms colonies in the wild by both thick, slowly spreading rhizomes and self-seeding. It attracts bees and is a larval host to the common buckeye butterfly the verbena moth, and the verbena bud moth.
 
This is a Watch List species (pdf) with limited occurrence in NC. Click to see its range in NC.
 
More info here