Blue vervain is a native, perennial wildflower that grows from 2 to 5 feet tall. Its hairy, square stems can be green or red. The toothed, lance shaped leaves progress in pairs up the stem and are about 6 inches long by 1 inch wide. Purplish-blue flowers bloom in multiple, showy, elongated panicles (flowers arranged on a stem) and are up to 5 inches long. Each bloom is about 1/4 inch across and conspicuously lobed. Blue vervain blooms in mid to late summer; approximately 1 1/2 months after blooming each bloom gives way to four oblong, reddish-brown, triangular-convex ?nutlets.? Blue vervain spreads through rhizomes, horizontal roots that produce new plants.