Japanese Stiltgrass

Microstegium vimineum var. imberbe

Alternate names
Mary's Grass, Basketgrass, Microstegium, Annual Jewgrass

Weed Description
Prostrate to erect summer annual grass that thrives in shaded areas. This grass weed roots at the nodes and therefore may quickly spread into shaded areas like backyard lawns, ditches, roadsides, etc.

Leaves
Rolled in the shoot, 3 to 10 mm wide, sparsely hairy on both surfaces. Most leaves have a distinct white midvein, however a key identifying feature of this grass is that the midvein does not divide the leaves into equal halves. For example, one side of the leaf separated by the midvein will be much larger than the other side of the leaf (shown in picture below). Leaves have a very short (0.2 mm), ciliate membranous ligule and no auricles.

Stems
Round, often hairy at the top, and capable of rooting at the nodes.

Flowers
Seedhead composed of 1 to 6 terminal spike branches.

Roots
A fibrous root system.

Identifying Characteristics
Leaf shape and habitat (shade-loving) are the primary features that help to distinguish this grass from other grasses. Few, if any, grass weeds have a midvein that does not proportionally separate an individual leaf.

Office of Programs

University of Missouri

Japanese Stiltgrass

Microstegium vimineum var. imberbe