Blue vervain is thought to have had a relatively recent origin. It developed from one of the white vervains, with transfer of pigment from the blue/purple group. One still sees intermediate, presumably hybrid plants like the one shown here. This is called Verbena x englemannii, and has been reported from AR, CT, GA, IA, IL, IN, KS, KY, MA, MD, MI, MO, NC, NH, NJ, NY, OH, OK, PA, TN, TX, VA, and VT. The white parent, V. urticifolia, is a more eastern plant, which of course also limits the range of the hybrid.