Here's a close relation to your garden vervain, which are derived from G. canadensis. These are small plants, not more than a foot tall, and tend to sprawl. They are very very similar to V. pulchella, and have much the same range. None of my references treat both species, and differentiate them in any way that is really clear and consistent. So we're a little out on a limb here calling this Dakota. Both species grow in dry open areas whether natural or disturbed. Certainly eye catching wherever and whichever. They're often on roadsides. Assuming this is V. bipinnatifida, you might see it in AL, AR, AZ, CA, CO, GA, IN, KS, KY, LA, MO, MS, NE, NM, OK, SD, TN, TX, WI, and WY. Morton Co GA, 3/15/16.