Tall Oatgrass

(Arrhenatherum elatius)

  • Cool season, loosely-tufted, perennial bunchgrass, 28-70 inches tall
  • In the grass family (Poaceae
  • Begins growth in early spring and remains green late into fall
  • Reproduces by seed and is sometimes rhizomatous
  • Leaf blades are 2-12 inches long and ⅛ to ⅓ inches wide, flat and smooth, rarely hairy or rough.
  • Ligules are short, square and hairlike. Sheaths are smooth.
  • Seedhead is a panicle, 3-12 inches long and up to 3 inches wide, green, shiny and occasionally purple-tinged. 
  • Panicle branches are 6-8 inches long, whorled and usually spikelet-bearing to the base
  • Native to Europe, western Asia, and northern Africa
  • Prefers sun to partial shade, well-drained moist soils but tolerates poor and dry soils.


Known Distribution

There are few occurrences of this species documented in Colorado. View the known North American Distribution Map. If you are aware of infestations that are not represented, please report your sighting. Register for an EDDMapS account, then select "Report Sightings". Please include photos with your submissions.