The top stem segment supports the seedhead, which in the case of Italian ryegrass is a solitary spike that ranges 4 to 16 inches long (typically 12 inches) and consists of alternately arranged spikelets that attach edgewise (parallel) directly to the flowering stem. Quackgrass seeds are arranged perpendicular to the flowering stem. Short awns (bristles) on spikelets and at least 10 florets per spikelet help differentiate Italian from perennial ryegrass (see pictures). The root system of Italian ryegrass is highly branched and dense, with many fibrous, adventitious roots. While the root system is primarily shallow, it can be very extensive.
Italian ryegrass regenerates entirely by seed and germinates readily with sufficient moisture. The plant is best adapted to cool, moist climates, and grows best between 68 and 77°F. It is highly shade intolerant but can adapt too many climatic conditions. Italian ryegrass grows in a wide range of soil types, although it prefers fertile, well-drained soils.
Italian ryegrass is a problematic weed in cereal crops and grass seed crops. It establishes quickly and grows rapidly. For that reason, in certain areas it is planted as a cover crop and quick food source. Italian ryegrass is very palatable and nutritious for livestock and most wild ruminants and is planted in many pasture settings.
Prevention: Prevent introduction of ryegrass onto property by ensuring that seed, feed, and equipment are free of ryegrass contaminants. Control is becoming more difficult every year due to its adaptability, high seed production, and adapted tolerance (resistance) of many herbicides used for control.