Verbena hastata (Swamp Verbena)
Family:
Verbenaceae (Vervain)
  
Verbena hastata grows in moist areas such as streambanks and wetlands. Plants grow up to 5 feet tall and are topped with several spikes of blue-purple flowers. Leaves are toothed and are often hastate (arrow-like, with two basal lobes pointing outward)

Vegetation zone:  Plains, Foothills
Time of bloom:  July - September
Origin:  Native
Eastern Colorado Wildflowers