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Real World Concerns with Old World Bluestems

James L. Ungerer, Rangeland Management Specialist
Manhattan, Kansas

Rapid expansion of Old World Bluestems (OWB) is an ever-growing concern and a very real threat to native prairies. As more land managers discover the presence of OWB on their prairies, the need to address this challenging resource concern is long overdue.

Caucasian and yellow bluestems were introduced into the United States in the early 1900s for use as forage and erosion control. It is now realized these invasive species have created extreme problems on the landscape. OWB appear to accelerate erosion on rangelands because they can cause an altered carbon-to-nitrogen ratio that inhibits the growth of native plants. These grasses are also less palatable to livestock, in comparison to native bluestem species, and can tolerate extreme grazing pressure. Invasive species, like OWB, harm the natural ecological systems of native prairies. If left uncontrolled, OWB will damage ranching economies to the point of threatening cattle produers’ livelihoods due to the extreme costs and profit loss. As OWB invades and takes over rangelands, native wildlife is also negatively impacted.

OWB grasses spread by root and by seed. They are prolific seed producers and the length of seed viability in the soil is unknown. Spread may be attributed to machine, animal, or wind. OWB often invades or occupies difficult to control areas in pastures or rangeland.

Early detection is key to addressing and controlling of OWB before it can completely take over a landscape. However, identification of these grasses can be difficult to the untrained eye looking out across the native prairie. Fall season is a good time to view it on the landscape because it will appear in dense, shiny blond patches, in comparison to the reds and maroons of native plants.

During the growing season, it will exhibit a much lighter green color than many native grasses. Many land managers first realize the presence of OWB when they observe dense stands that cattle graze right up to and stop.

At this time, strategies to deal with OWB require an ever changing approach to treatment, management, and control. If seeding new grass stands, be sure that mix is not contaminated with OWB seed.

When feeding hay on rangeland, be certain that it does not contain OWB. Producers need to realize other ways it spreads and take necessary precautions and preventions against OWB expansion. Chemical treatment of OWB includes spot application following Kansas State University recommendations and appropriate product labels.

Prior to any herbicide treatment, mowing, or prescribed burning of patches during the dormant season, early spring, is recommended to remove standing dead plant material to maximize chemical contact with live-plant material. Post-application monitoring of treatment and follow-up treatments should be repeated as needed. Others have used livestock to heavily graze areas with OWB to control seed production of the grasses.

Educating others to the potential risks of OWB spread, detection, treatment options, and ultimate negative impacts is key to addressing this rapid concern. For questions regarding identification or treatment options of OWB, contact your local Natural Resources Conservation Service (NRCS) office.

For more information, visit the Kansas NRCS Web site www.ks.nrcs.usda.gov/programs or your local U.S. Department of Agriculture (USDA) Service Center. To find a service center near you, check on the Internet at offices.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider, employer, and lender.