This wild species of Verbena is identified as Rose Vervain (Verbena canadensis) in Carl Hunter's Wildflowers of Arkansas book.

You can see Rose Vervain growing along roadsides throughout HSV.
You may even find it growing wild in your yard.
You can also purchase Verbena/Vervain in nurseries.

Rose Vervain spreads well without being invasive, grows well in any kind of soil, and is drought resistant. It has fragrant blooms from Spring to Fall. The only drawback is that it seems to succumb to some kind of fungus and dies out, but when it does, we just transplant some from elsewhere in the yard.

All of the vervain shown in these pictures have since died out and been replaced with more. To try to combat this die-out, I am now (May 2016) treating them with Bayers 3-In-One for Roses and Gardens. In addition to plant food, it has a fungicide and pesticide.

Verbena matching the Redbud tree (on the right)

Verbena in front of the Cotoneaster bed. May 5, 2013:

May 3, 2015:
Garlic and verbena in the southwest bed along the edge of the golf course. The garlic helps keep the deer away.