Smooth Brome (Bromus inermis)

A large brown seed head on a stem of grass.

NPS/Gordon Dietzman

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Smooth brome can grow up to a height of 4 feet with basal and stem leaves of 4 to 10 inches growing at the tip of the stem. The leaves are a wrinkly shape W near the stem. As the grass matures, the flower changes to a purplish-brown color.

Smooth brome is leafy perennial grass that thrives during the cool season, so it grows best early in the year and spreads quickly, out-competing native plants for nutrients and water. They are sod-forming and have a rhizomic root structure that allows them to disperse effectively. Rhizomes are 'underground stems' growing horizontally much like those above ground grow vertically. As they spread through the ground, plants will sprout from these 'stems.' Their root structure allows them to tolerate periodic floods and live through droughts. Smooth brome may go dormant if conditions are not favorable.

Introduced to the United States from Europe and eastern Asia in 1884, smooth brome was, and still is, used as a food for livestock and for erosion controls. Except for Alabama, Georgia, Hawaii and Florida, smooth brome grow throughout the United State. Its thrives mainly in open areas such as roadsides, riverbanks, open fields and woodland edges.

Want to Help Us Better Understand the Park?

See our iNaturalist project, "The Life of the Mississippi National River and Recreation Area" and contribute to it by downloading the iNaturalist app and uploading your sightings of this species, and others, to the project. You can also upload your sightings from your computer.

Last updated: March 22, 2018

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