Liriope muscari (Decne.) L.H.Bailey big blue lilyturf, lilyturf, border grass, and monkey grass

a species of low, herbaceous flowering plants from East Asia. Common names in English include - wp

http://plants.usda.gov/core/profile?symbol=LIMU6 (gives family as Liliaceae)

Weakley gives family as Ruscaceae

Look for it where it persists or escapes after cultivation, per Weakley's Flora

Non-native: China, Japan & Taiwan; Documented growing wild in GA NC SC

This plant may be causing problems in natural areas outside its native range, according to authorities such as:

Georgia Exotic Pest Plant Council, 2006

SC Exotic Pest Plant Council, 2014

US Forest Service Southern Research Station

20160709 Under the northernmost crepe myrtle.