Old World Bluestems

Yellow and Caucasian Bluestems are emerging as possibly the greatest long-term invasive threats to the natural integrity of native prairie rangelands, hay meadows, and prairies in Kansas and the central Great Plains.

OWBphotoOld World Bluestems on Kansas Roadside. Photo by Ron Klataske

How they spread. From roadsides where they often get their start on disturbed sites, possibly from contaminated seed mixtures provided by contractors or from mulch and further spread up and down roadsides by mowing machinery. Haying of roadsides presents the added prospect that they may be unknowingly spread to distant pastures–possibly even by livestock producers who purchase hay harvested on roadsides and have no idea that it includes seed of these highly invasive plants. If these non-native invasive grasses continue to overtake pastures they will be difficult and expensive to control. The most obvious spread of OWBs is within and from roadsides, Corps of Engineers dams and levees (particularly apparent at Tuttle Creek Dam and on levees along the Kansas River in Manhattan) and other disturbed sites.

The Problem. There are no available selective herbicides effective at eliminating them. Entire plant communities within areas infested by these Old World Bluestems have to be sprayed with herbicide cocktails, killing most or all of the other plants as well. If control is undertaken soon–particularly by the Kansas Department of Transportation, county road departments, and other county, municipal, state and federal agencies–the costs will be manageable. The same is true for private landowners. However, if swift action is delayed and OWBs continue to spread, the cost of control and damages will likely be in the tens of millions of dollars, and as they spread across private land most of the burden of costs and damage to rangeland resources will be on the backs of landowners. In most circumstances cattle do not like to eat these Old World Bluestems if they have native rangeland or other grasses in the pasture as an alternative.

Ecological Damage. These Old World Bluestems make grasslands relatively unsuitable as nesting, brood rearing, or year-round habitat for many grassland birds (including Prairie-chickens), and it is unsuitable as habitat for many other species of wildlife. The presence of these OWBs even changes the soil chemistry and biology to render soil unsuitable for germination of most native plant seeds. Thus, restoration of native prairie or even other introduced pasture plants is MUCH more difficult. The mulch (with water running through it) can even be toxic–preventing germination of native plants.

Our Role. To educate citizens, landowners, state agencies, and legislators about the threats of OWBS and provide identification and eradication tools. We are urging our legislators to list Caucasian and Yellow Bluestems as noxious weeds and are strongly encouraging KDOT to take the Old World Bluestem threat seriously and implement a plan to curtail it by 1) identifying it along KDOT managed properties, 2) initiating an aggressive spraying program (possibly eliminating or at least reducing non-essential mowing to redirect funds), and 3) prohibiting private haying operations or removal on all areas where it is found on KDOT rights-of-way.

Watch the video from the Caucasian and Yellow Bluestem Workshop AOK hosted in April.