Control of Old World Bluestems

Because Caucasian and yellow bluestems are perennial species and grow from their established root systems, there is a very limited number of methods available for Native or controlling them. • Because of their deep and extensive root systems, they cannot be dug, tilled or pulled. Invasive?

• They are fire-adapted species so they thrive in the annual burns that are so good at keeping other weeds at bay.

• There are no biological controls available because of the possibility that the agents would harm our native species as well.

• Because they are so closely related to our native bluestems, there are no herbicides available that will control the invasives without hurting the natives and other desirable species. For more information on the state weed program, go to: • The only herbicides that have shown success at www.agriculture.ks.gov/noxious-weed controlling both species of Old World Bluestems Dr. Walt Fick, KSU are:

Glyphosate Applied at 1-2 lbs. / acre will effectively control the old world bluestems but will also kill any native or desirable species. A Guide to the

Imazapyr Kansas Department of Agriculture Bluestem Grasses Applied at 0.25 - 0.5 lbs. / acre is less efficient at 1320 Research Park Drive controlling the old world bluestems but is also less of Kansas Manhattan, KS 66502 harmful to the natives. (785) 564-6698 Invasive Bluestems Old World Bluestems Native Bluestems in Kansas

Yellow Bluestem The native prairies of Kansas are in the midst of an Big Bluestem Bothriochloa ischaemum invasion by aggressive intruders that are pushing our Andropogon gerardii

native bluestem species away as they take over our Yellow bluestem is a perennial, formerly pristine landscapes. Big bluestem can be disting- clump-forming, small, blue-gray uished from other warm-season graceful grass, with flowering The interlopers are the old world bluestems, two exotic grasses by its purplish, 3-part stems up to 4 feet tall. It has species that were introduced into the United States in flower clusters that resemble a yellow-green leaves that are the early 1900s as forage species. The two species of turkey’s foot. The stems are usually smooth and grow up to old world bluestems are yellow bluestem (Bothriochloa erect, up to 10 feet tall, stout, 10 inches in length. The leaf ischaemum) and Caucasian bluestem (Bothriochloa and are usually covered with a blades are flat or folded. The bladhii). Both of these species have had several cultivars blue-tinted waxy layer. Leaf stem joints may be smooth or bred from them, all of which are invasive. blades are flat, 6-24 inches long, with short hairs. The silvery, Both species are found throughout Kansas; in fact, one smooth below and rough reddish-purple flower head is or both of them have been reported in 98 of our 105 above. The flower head is similar to that of big bluestem counties. Having established themselves in such large typically composed of three except that there are more numbers, there is little to no chance of eradicating them robust spike-like branches, but USDA branches and they are much from Kansas without spending large amounts of money. can have as many as seven. finer with smaller seeds. It blooms in late June to July, Flowering takes place July through October. The foliage earlier than the native bluestems. Other than being able to spread to new areas quickly stems stay upright through the winter. and easily, one of the reasons they are impacting our pastures and native prairies so much is that they both Caucasian Bluestem produce natural chemicals that prevent any other Little Bluestem Bothriochloa bladhii species from growing around them, reducing Schizachyrium scoparium competition for water and nutrients and creating large

areas where nothing else can grow. Caucasian bluestem is a small Little bluestem is one of the dominant grasses in the blue-gray grass, with flowering Being able to identify the Old World Bluestems and tallgrass prairie. It is a native, stems that can reach 1 to 3 feet telling them apart from our native species is the first warm-season grass which high. It forms dense tufts of step in controlling them. While they are so much alike typically grows 2-4 feet tall and smooth leaf blades, up to 12 in early spring that even the experts can’t tell them occurs throughout most of the inches long with a thickened apart, after they flower it is fairly easy to identify them. state. It forms upright clumps of mid-vein. The stem joints are In the late summer and fall they become very light slender green leaves with a purple-tinged and may be colored and stand out easily amongst the darker native tinge of blue at the base. smooth or with short hairs. It grasses. blooms in late June to July, far Purplish-bronze flowers appear earlier than our native in 3-inch long heads on bluestems. The flower head branched stems rising above the foliage in August. Resulting University of Missouri features side branches that are shorter than the central stem, clusters of fluffy, silvery-white and resembles a miniature Johnsongrass, which seed heads are attractive and may persist into winter. blooms at the same time. The most outstanding feature of this grass may be the bronze-orange fall foliage color.

Kansas State University