green foxtail

Green foxtail, also called green bristle grass, is an exotic, small, weedy grass. It is native to Europe, Asia, and northern Africa. It was introduced into North America where it now occurs throughout the United States and southern Canada. It is very common in Minnesota, and has been recorded in 80 of the state’s 87 counties.

Several varieties of Setaria viridis have been described. Two varieties are generally recognized as occurring in North America. Only the nominate variety Setaria viridis var. viridis is common and widespread.

Green foxtail is found in a variety of cultivated and disturbed areas, including in vacant lots, gardens and lawns; on roadsides and railroad rights-of-way; in cracks in parking lots and sidewalks; and at the edges of agricultural fields. It grows under full sun, in moist to moderately dry conditions in many types of soil. It is fast growing and short-lived, producing several generations of plants in a single growing season.

The nominate variety Setaria viridis var. viridis typically grows to a height of 20 to 60 cm.

The stem is slender and erect, and may be branched or unbranched depending on the growth conditions. It is typically green, with a slightly ribbed or grooved surface, and can be up to 3 mm in diameter.

The leaves are narrow and elongated, with a length of 5-20 cm and a width of 2-8 mm. They are arranged alternately along the stem and have a rough texture.

The inflorescence is a densely packed spike that is cylindrical or slightly tapered at the top. The spike can be up to 10 cm long and is composed of numerous small, spikelet-like structures that contain the flowers. The spikelets are arranged in pairs along the spike, and each spikelet contains one to three flowers.

The flowers are small and inconspicuous, and less than 1 mm in diameter. They do not have showy petals or sepals.

The fruit is a small, egg-shaped or elliptical capsule that contains one to three seeds. The seeds are small, shiny, and yellowish-brown in color, with a length of about 1-2 mm.

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