Japanese Stiltgrass Information
Japanese stilt grass is an annual grass that can reach 5 feet in height, but tends to grow 1 - 3 feet in a branching, sprawling, mat-like manner. Its pale green leaves alternate along a branched stalk, resembling a small, delicate bamboo. Leaves are narrow, lance-shaped, up to 3 inches long and lightly hairy. A distinguishing feature is a pale, silvery stripe of reflective hairs along the midrib of the upper leaf surface. Flower spikes - 1 to 3 inches long - appear in September and produce seed by early October.
The native perennial whitegrass or Virginia cutgrass (Leersia virginica) is similar, but lacks the silver stripe along the midrib. Stilt grass flowers late -- in mid-September -- and whitegrass flower spikes appear in August. The nodes (where leaves emerge) of stilt grass are smooth, but are hairy in Leersia. In fall, stilt grass turns yellow to pale purple, while whitegrass stays green. A non-grass look-alike is smartweed or lady's thumb (Polygonum persicaria). It can form masses of grass-like plants, but its leaves have a dark blotch and flowers are pink and bead-like.Check out the Stiltgrass vs. Whitegrass Document for characteristics defining the two.