White vervain (Verbena urticifolia var. urticifolia) is common throughout most of Minnesota. It blooms from June to October in areas of partial sun in woodland edges and openings, thickets, power lines, trails, and other disturbed sites.
This plant is difficult to photograph in its entirety. The flower spikes spread widely in all directions and the individual flowers are tiny. The inflorescence tends to get lost against the background and most of it is inevitably out of focus.
There are two varieties of white vervain and both are found in Minnesota. This variety, var. urticifolia, is distinguished by fewer and longer hairs on the underside of the leaf blade; visible appressed hairs on the calyx; and a slightly longer nutlet that is corrugated on the back.