Ohio Perennial and Biennial Weed Guide

Family:

Grass Family (Poaceae)

Other Names:

Muhlenbergia communtata, Muhlenbergia mexicana, dropseed grass, knot-root-grass, Mexican drop-seed, satin-grass, wood-grass.

Origin and Distribution:

A grass species native to North America, wirestem muhly is common in the eastern and north central U.S. and is found throughout Ohio. Outside of agricultural fields, wirestem muhly grows on roadsides, stream banks, ditches, orchards, and other areas with rich, moist soils.

Plant Description:

Wirestem muhly is a creeping, sod-forming perennial grass, characterized by a leafy, bushy appearance resulting from a freely-branching growth habit. It reproduces by seeds and rhizomes (horizontal underground stems). Plants can expand by producing new shoots (tillers) from the base of existing stems, and through stolons (horizontal stems at the surface of the ground that root at the nodes).

• Root System:

  Wirestem muhly produces very scaly, short, thick, creeping rhizomes (horizontal underground stems) near the soil surface. Fibrous roots are produced from the joints (nodes) of the rhizomes.

• Stems:

  The leafy stems (2 to 3 1/2 feet long) can be erect or sprawling, almost horizontal to the ground. Stems are smooth, stiff, wiry, round and many-branched, with branching branches. They are sometimes purplish in color. Reclining stems can root at the nodes.

• Leaves:

  Leaves are rolled in the bud. The pale green leaves are produced along the stems, but are densest near the tips, giving the plant a bushy look. The leaf blade (free part of the leaf) is relatively short (1 to 4 inches long, 1/4 to 1/3 inch wide), flat and somewhat blunt-tipped. The upper and lower surfaces of the blade are hairless and usually rough. Leaf margins are rough. The leaf sheath (part of the leaf surrounding the stem) is smooth and rounded, with overlapping margins. The ligule (projection inside on the top of the sheath) is membranous, jagged and short (1/25 inch long). Auricles (appendages at the top of the sheath) are absent.

• Flowers:

  Small flowers are densely arranged in a narrow, branched flower head (1 1/2 to 4 inches long, 1/3 inch wide). Flower heads are produced at the ends of stems and in the axils of most leaves, remaining partially protected in the leaf sheath. Flowers change from soft green to brown-purple as they mature.

• Fruits and Seeds:

  The light brown seeds are approximately 1/16 inch long.

Similar Species:

Wirestem muhly may be confused with nimblewill (Muhlenbergia schreberi) and quackgrass (Elytrigia repens). Nimblewill can be distinguished by its lack of rhizomes, delicate appearance and shorter stature. Quackgrass can be distinguished by its smooth, pointed rhizomes (versus the very scaly rhizomes of wirestem muhly), and the long, claw-like auricles at the top of the sheath.

Biology:

Wirestem muhly flowers from August to October. This species reproduces primarily through its scaly rhizomes, and new plants can easily establish from small pieces of rhizome. An individual plant can produce approximately 450 rhizomes in one season. In addition, plants can enlarge by producing tillers (new shoots from the base of existing stems), as many as 200 per plant per season. Most other grasses have fewer stems per plant than wirestem muhly.

Prior to 1950, wirestem muhly was not considered a common agronomic weed. The emergence of this weed in agronomic systems coincides with the introduction of herbicides that are ineffective against wirestem muhly, and reduced tillage, which allowed it to spread from field margins. Because new plants can form from rhizome fragments, wirestem muhly is often spread from field to field by farm equipment. Repeated tillage is reported to help control this grass by breaking up the rhizomes into smaller and smaller pieces and continually bringing the pieces to the surface, where they desiccate. However, infrequent cultivation can actually increase a wirestem muhly problem because it breaks up the rhizomes, but leaves many of the rhizome fragments buried, where they can form new plants.

Toxicity:

None known.

Facts and Folklore:

• The genus Muhlenbergia is named for a famous 18th century American botanist, Dr. Rev. Henry Muhlenberg, whose father was the founder of the Lutheran Church in the U.S.