Quackgrass

Quackgrass is a perennial grass in the Poaceae family. It produces erect stems that may reach 4 feet tall and form clumps. These stems may be smooth or hairy. Leaves and stems are green. Leaves are flat and narrow (0.3 - 16 mm wide) while varying in length from 1.5 to 12 inches long. The upper leaf surface may be smooth or slightly hairy. Leaves have a small pinch or indentation 1 to 2 inches from the leaf tip. Sheaths are open around the stems. Ligules are small, membranous, and fringed, and auricles are thin and clasp the stems. Auricles may be white, green, or reddish. Quackgrass flowers from mid-spring to late summer. Flowers are produced on a 2 to 8-inch spike with spikelets occurring alternately. Seeds are formed in small awns. Quackgrass has a large root system made of fast-growing rhizomes. Tips of rhizomes are pointed allowing for penetration through soil and roots of other plants.

Quackgrass is native to Eurasia. It was introduced to North America with some of the first European colonists in the 17th century likely as a contaminant in hay. It creates dense infestations by spreading rhizomes and spreads to new locations by seed or root fragments. Quackgrass can be found in a variety of areas including agricultural fields, riparian areas, roadsides, forests, rangeland and pastures, gardens, landscapes, and lawns.

Prevention strategies and cultural control strategies should be utilized as much as possible.

There are not currently any biological control agents available for quackgrass.

Hand pulling and digging out of rhizomes is not recommended because rhizome fragments are capable of resprouting, although small patches may be removed by hand. Mowing is also not effective. Aggressive tillage techniques, such as moldboard plowing, may be effective but are frequently impractical in the shallow, rocky soils of Teton County. Grazing is also not frequently effective, and care should be taken as ergot, a poisonous fungus, can be found on quackgrass.

Infestations can be controlled with herbicides. With many herbicides, treatment before the shoots reach 8 to 12 inches tall is preferred. Some herbicides can be utilized for late-season treatments to reduce rhizome biomass. Read the label before using any herbicide. Contact TCWP if you have any questions about application rates or how to use an herbicide.

• Weed Report: Quackgrass (2013) DiTomaso, J.M.,G.B Kyser et al. Weed Control in Natural Areas in the Western United States. Weed Research and Information Center, University of California. https://wric.ucdavis.edu/information/natural%20areas/wr_E/Elytrigia.pdf
• Weed of the Month: Quackgrass. Patton, A. and Law, Q. Purdue University https://turf.purdue.edu/quackgrass/
• How to Get Rid of Quackgrass: Will you live with it or control it? (2023) Miller, W., Mann, J.J., and Buhl, K. Oregon State University Department of Horticulture https://solvepestproblems.oregonstate.edu/weeds/quackgrass
• Quackgrass Management: An Integrated Approach (2017) Lingenfelter, D. and Curran, W.S. Penn State Extension. https://extension.psu.edu/quackgrass-management-an-integrated-approach