Annual Ryegrass

Lolium multiflorum

Alternate names
Annual Rye; Italian Ryegrass

Weed Description
A winter annual that may reach 3 ft in height with conspicuous auricles and a distinctive seedhead. Found throughout the United States, primarily as a weed of small grains.

Leaves
Rolled in the bud with conspicuous claw-like auricles in the collar region. Leaf blades are 2 1/2 to 8 inches long, 4-10 mm wide when mature, and have a membranous ligule. Leaves usually have a glossy appearance on the lower surfaces.

Stems
Leaf sheaths are often tinged red at the base.

Flowers
The seedhead is a spike (4-16 inches long) with spikelets that have long awns arranged alternately up the stem.

Roots
Fibrous.

Identifying Characteristics
The auricles that occur in the collar regions distinguishes this grass from other similar weeds, as relatively few grass weeds have this feature. Additionally, the red-tinged base of annual ryegrass helps to distinguish this weed from perennial ryegrass (Lolium perenne), which is very similar in growth habit and appearance.

Office of Programs

University of Missouri

Annual Ryegrass

Lolium multiflorum