purple love grass
Eragrostis spectabilis

Hardiness: Zones 5 to 9
Plant type: Grass
Height: 1- 2'
Spread: 1- 2'
Sun: Full Sun
Water: Dry to medium
Bloom time: July, August
Bloom color: Soft reddish-purple
Soil: Average, well-draining soils, sandy, or gravelly loams, tolerates poor soils. 

Notes: Hosts caterpillars of the Zabulon skipper.  Birds forage on the seed but foliage is not palatable to deer. Eragrostis spectabilis is salt tolerant enough to flourish on roadsides that receive winter salt.

More information on this plant here.