Hierochloa odorata is a species occuring in moist meadows and other damp places;  it is known as sweetgrass, or vanilla grass.  Traditionally, it is  braided &  used as incense, as smudges, and to make fragrant baskets.  It is a runner, spreading by rhizomes.

Hierochloa odorata     green leaves, 18"-2'    flowers to 2' tall    does best in moist ground     zone 4