Blue vervain (Verbena hastata) is common throughout Minnesota, possibly occurring in every county in the state. It blooms from July to September in marshes, meadows, fields, swamps, and roadside ditches. The densely crowded flower spikes bloom from the bottom up and only one to a few complete rotations of the spiral are in bloom at any one time.
Blue vervain is distinguished from hoary vervain by its green (not grayish-green) foliage; long, narrow, noticeably stalked leaves that are inconspicuously short hairy; inflorescence of 5 to many spikes; and distinctly pointed flower spikes. There are two varieties of blue vervain, both of which occur in Minnesota. This variety (var. hastata) is distinguished by the presence of one or two lobes at the base of the larger leaves.