giant foxtail
(Setaria faberi Herrm.)

Overview

Appearance

Setaria faberi is an annual grass that can reach 2-5 ft. (0.61-1.5 m) in height.

Foliage

Leaves are up to 16 in. (41 cm) long, 0.6-1 in. (15-25 mm) wide. Sheath is round with hair on margins. Blade has short hairs cover the upper surface. Ligule has a fringe of hairs. There are no auricles.

Flowers

Flowering occurs in late summer to early fall, when a green (eventually straw colored), bristly inflorescence develops. The inflorescence resembles a foxtail, hence the common name.

Fruit

The fruit are small flattened ovoids with hard coats. They usually germinate in late spring to early summer.

Ecological Threat

Setaria faberi is native to Asia and was accidentally introduced in the United States in the 1920s as a contaminant of other grain. Plants invade disturbed sites such as roadsides, landfills, fence rows and right of ways.

Herbicide Resistance

Populations of this plant exist in the United States that are resistant to ACCase inhibitors (A/1), ALS inhibitors (B/2), and Photosystem II inhibitors (C1/5).

Resources

• Weed of the Week - USDA Forest Service

Selected Images

Maps

Invasive Listing Sources

• California Noxious Weeds
• Georgia Exotic Pest Plant Council - Category 4
• Invasive Plant Species of West Virginia
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• Kentucky Exotic Pest Plant Council - Significant Threat
• Kentucky Noxious Weeds
• Maryland Code and Regulations Noxious Weed & Seed Law
• Michigan Noxious Weeds
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999

References