USDA 

- United States Department ofAgriculture

Field Guide for Managing Yellow

and Caucasian (Old World)

Bluestems in the Southwest 

Forest Southwestern 

Service Region TP-R3-16-36 October 2018 
 

 

 

 

 

 

 

 

 

 

 

 

 

Cover Photos 

Top left — Yellow bluestem; courtesy photo by Max Licher, SEINet 

Top right — Yellow bluestem panicle; courtesy photo by Billy Warrick; Soil, Crop 

and More Information 

Lower left — Caucasian bluestem panicle; courtesy photo by Max Licher, SEINet 

Lower right — Caucasian bluestem; courtesy photo by Max Licher, SEINet 

Authors 

Karen R. Hickman — Professor, Oklahoma State University, Stillwater OK 

Keith Harmoney — Range Scientist, KSU Ag Research Center, Hays KS 

Allen White — Region 3 Pesticides/Invasive Species Coord., Forest Service, Albuquerque NM 

Citation: 

USDA Forest Service. 2018. Field Guide for Managing Yellow and Caucasian (Old World) 

Bluestems in the Southwest. Southwestern Region TP-R3-16-36, Albuquerque, NM. 

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Yellow bluestem (Bothriochloa ischaemum (L.) Keng)

Caucasian bluestem (Bothriochloa bladhii (Retz.) S.T. Blake, synonym: B. caucasica

(Trin.) C.E. Hubb.) 

Grass family (Poaceae), Andropogoneae tribe 

Yellow and Caucasian bluestems are introduced 

bunchgrass species that are becoming invasive in 

southwestern States after successfully invading the Central 

and Southern Great Plains. This field guide serves as the 

U.S. Forest Service’s recommendations for management of 

yellow and Caucasian bluestems in forests, woodlands, 

rangelands, desert, and desert scrub associated with its 

Southwestern Region. TheSouthwestern Region covers 

Arizona and New Mexico, which together have 11 national 

forests. The Region also administers 4 national grasslands 

located in northeastern New Mexico, western Oklahoma, 

and the Texas panhandle. 

Description 

Yellow bluestem (Bothriochloa ischaemum) and 

Caucasian bluestem (Bothriochloa bladhii) are perennial 

mid-grasses that belong to a group of non-native bluestems 

collectively referred to as Old World bluestems (OWBs). 

The term Old World bluestem is a shared common name 

for approximately 65 species in the closely related genera 

of Bothriochloa Kuntze, Capillipedium Stapf, and 

Dichanthium Willemet. B. bladhii is used synonymously 

with B. caucasica, which is nearly similar in morphology 

but has an uncertain taxonomy. 

Common names for yellow bluestem include King Ranch 

bluestem and Turkestan beardgrass; the most common 

cultivars are King Ranch, Plains, Ganada, WW–Spar, and 

WW–Iron Master. Caucasian bluestem is also called 

Australian beardgrass (or bluestem), forest bluegrass, and 

purple plume grass. It has a single cultivar named WW-B. 

Dahl. OWB cultivars were developed from introduced 

germplasm and have been selected for different disease 

and insect threats, climates, and soil-site conditions. 

Yellow bluestem derives its name from its yellow-green 

culms and leaves. Caucasian bluestem has dense bluegreen leaves, and some plants can be strongly aromatic. 

Close similarity to native bluestems makes early 

identification of the two OWB species difficult in the 

spring. Positive identification generally can only be made 

after panicles have developed. Resources for identifying 

these two bluestem species can be found in the Photo 

Image Libraries subsection at the end of this document. 

OWBs are native to Eurasia, Africa, and Australia. They 

were first introduced into the U.S. in the early 1900s and 

have been planted widely throughout the Central and 

Southern Great Plains for forage and for erosion control in 

disturbed areas such as roadside rights-of-way (ROWs). 

OWB seed is readily obtained from many seed companies. 

Growth Characteristics 

Both OWB species – 

• Are warm-season, perennial bunchgrasses that are

relatively shade-intolerant; typically, they have

rhizomes (underground stems) and stolons (aboveground stems) under close grazing or cutting. Yellow

bluestem has a more rhizomatous growth form

relative to Caucasian bluestem’s bunchgrass

(caespitose) growth form. Although the early growth

form of yellow bluestem is an erect bunchgrass,

older stands tend to form a sod.

• Produce spindly looking, flowering culms/tillers that

are 2–4 feet tall, depending on moisture. The two

species have reproductive and vegetative

culms/tillers that are roundish with varying amounts

of hair; leaves typically are 0.25 to < 0.5 inches wide

and 8-12 inches in length, flat or folded.

• Can initiate rapid growth in the summer and

reproduce earlier than native species, which actually

deters grazing.

• Produce reddish-purple inflorescences; some cultivar

inflorescences may turn fawn to white-colored at

maturity. Yellow bluestem’s inflorescence is a fan or

finger-like panicle; Caucasian bluestem has a panicle

that is pyramidal or evergreen tree-shaped.

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• Readily germinate from seed and establish

reproducing populations within one growing season;

such features are highly desirable for hay production.

Both OWB species are prolific seed producers, and

extensive seed banks can develop in soil.

Ecology 

Impacts/Threats 

Once established, OWBs can be highly invasive and have 

the potential to form biodiversity-inhibiting monocultures 

that can transform grassland vegetation at the community 

and ecosystem levels of organization. OWB monocultures 

lack the necessary variety in structure, seasonality of growth, 

and nutritional availability required to sustain a diverse 

fauna. Floral diversity may be impacted directly by OWBs 

through physical displacement, competition, etc. Habitats of 

some Threatened and Endangered (T&E) species in 

particular can be threatened by OWBs. In combination with 

other less desirable non-native grass species such as 

Lehmann lovegrass (Eragrostis lehmanniana), OWBs may 

form a complex that can act similarly to a monoculture. 

Pastures and grasslands invaded by OWBs support fewer 

insects (a vital part of the food chain) as they lack forbs, 

which typically host more insects than wind-pollinated 

grasses. The reduction in forbs may particularly impact 

native pollinators such as bees and butterflies. In addition, 

the loss in insect activity could ultimately lead to lower 

numbers and diversity of songbirds. 

OWB infestations can alter carbon:nitrogen (C:N) ratios in 

soil and the composition of soil microbial communities, 

including arbuscular mycorrhizae. Growth of native plant 

species may be inhibited by these changes in soil properties. 

In addition, a recent study has found that an allelopathic 

toxin produced by yellow bluestem can reduce reproduction, 

growth, and survival of native bluestems. 

Heavy OWB infestations in pastures or native grassland may 

require changes in grazing management practices. Mature 

patches of OWBs are typically avoided by grazing animals, 

which can cause accumulation of residual dead standing 

material that is also avoided. High levels of dry matter 

accumulated in these patches may be prone to wildfire. 

Site/Distribution

OWBs can infest both disturbed and non-disturbed sites; 

however, they tend to establish more readily on disturbed 

sites. The two species can adapt to highly calcareous soils 

with high pH but do well on any well-drained soil. Yellow 

bluestem is best adapted for sandy loam to clay loam soils. 

In general, OWBs have relatively little cold tolerance, 

which makes them unable to withstand environments with 

extended periods of freezing winter temperatures. 

Caucasian bluestem is more tolerant to freezing and tends 

to occur in more northerly climes in the Midwest. Yellow 

bluestem is more common in the southern U.S. and is 

winter-hardy in the Central Great Plains only to about 40o 

N latitude. Both OWBs are found throughout Arizona and 

New Mexico, although Caucasian bluestem is relatively 

uncommon at this point in time. 

Spread 

Sites planted or invaded by OWBs serve as the primary

source for further spread onto disturbed and non-disturbed 

sites. In the Southwest, OWBs generally migrate away 

from infested roadsides or other disturbed areas in an

advancing front across pastures or native grasslands. If 

unassisted, OWB seed has relatively limited dispersion 

and will mostly establish seedlings close to parent plants. 

However, seeds readily disperse via mowing operations in 

ROWs, vehicular traffic, flowing water, animals, and 

winds moving across open terrain. Growth of stolons and 

rhizomes may also contribute to spread on a local basis. 

In the Southwest, State and county highway departments 

have used OWBs in seeding ROWs for erosion control. 

Use of OWBs was encouraged in the 1980s for 

Conservation Reserve Program (CRP) lands in Oklahoma, 

the Texas panhandle, and eastern New Mexico. Yellow 

bluestem was also planted during the Dust Bowl era on 

lands acquired by the Federal government for 

rehabilitation under the Bankhead-Jones Farm Tenant Act 

of 1937. Such widespread plantings have enabled OWBs 

to move northward into Nebraska and Missouri from large 

populations already present in more southerly States. 

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Invasive Features 

Both OWB species are quickly established, produce large 

numbers of seed, and can tolerate severe drought, heavy 

grazing, fire, and a limited amount of winter freezing. 

Many of the characteristics that make OWBs desirable for 

planting also promote invasion of pastures and native 

grasslands. For example, both OWBs are tolerant to 

drought and grazing; however, selecting these traits for 

forage production has increased their invasiveness. 

The most common use for OWBs is cattle forage, although 

cattle often find them less palatable than warm-season 

native grasses. Consequently, animals may avoid grazing 

OWBs in favor of native plants thereby giving OWBs a 

competitive advantage. 

Management 

Considerable information exists in regard to planting and 

managing OWBs for various agronomic purposes such as 

grazing, forage production, soil erosion prevention, 

reclamation, etc. However, there is much less experience 

and information available about controlling these grasses 

in areas where preservation of native plant communities is 

a primary management objective. Restoration of pastures 

or native grasslands dominated by OWBs has proven to be 

exceedingly difficult if not impossible. Studies conducted 

in the Great Plains with different OWB control methods 

have shown varying degrees of success. Results from these 

studies indicate that an integrated management approach 

generally improves the efficacy of herbicide control. 

OWBs are most effectively managed by preventing their 

spread. Preventative measures that can be taken include, 

but are not limited to: 

• Do not plant OWB seed for forage, erosion control,

reclamation, or other purposes.

• Do not mow OWB-infested areas in ROWs or other

corridors of transport once seedheads have started to

form.

• Do not feed grass hay from unknown sources or

from ROWs.

• Use power washers or air compressors with a blow

gun attachment to remove seed from vehicles after

going through OWB-infested areas.

• If re-seeding an area, do not use seed obtained from

equipment that has also been used to harvest and/or

process OWBs.

To manage OWBs, the following actions should be 

performed: 

• Detect, eradicate, or at least contain newly

established OWB populations as early as possible,

especially along roadways and waterways. In areas

where eradication or containment of these species

are no longer feasible, efforts should be made to

control their rate of spread.

• Report and map known OWB populations. Keep

annual records on reported infestations.

• Develop a specific action plan to meet goals and

objectives for established OWB infestations, which

may emphasize eradication of new OWB infestations

in sensitive areas such as T&E species habitat, travel

corridors, etc.

• Implement a plan for monitoring and follow-up

treatment of missed OWB plants and seedlings.

Also, monitor recovery of desirable native plant

species following control efforts.

Management Options 

Table 1 summarizes management options for common 

situations involving yellow and Caucasian bluestems. 

Further details on these management options are explained 

below. Choice of control method(s) for OWBs depends on 

many local factors including extent of infestation, current 

land use, and site conditions (terrain, accessibility, 

microclimate, presence of non-target flora and fauna, etc.). 

Other considerations include treatment effectiveness and 

cost, time needed to achieve control, and whether the 

management objective is eradication, containment, or 

slowing the spread of infestation. More than one control 

method may be needed for a particular site. 

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Table 1. Management options* 

Site Physical Control Cultural Control Biological Control Chemical Control 

Roadsides, Disk or plow tillable non- Test seed, forage, mulch, and Classical biocontrol Use truck or tractor-mounted 

fence lines, crop areas. fill materials for OWB seed. agents are unavailable. spraying equipment to 

or non-crop 

areas Use late season, long-term 

mowing to reduce OWB 

growth in spring. Since 

movement of seed can 

increase infestations along 

ROWs, do not mow once 

OWB flowering heads have 

started to form. 

Use native grass species or 

other desirable plant species 

when reseeding rights-of-way. 

Avoid driving vehicles and 

equipment through infested 

areas. Decontamination 

procedures should be 

implemented if travel through 

broadcast treat. Wash 

underneath vehicle after 

application to prevent seed 

spread. 

Burning used alone is not these areas is necessary. 

recommended as it will 

likely result in increased 

OWB densities; consider 

combining burning with 

herbicide spraying. 

Rangelands, Disk or plow if OWBs are Test seed, forage, mulch, and To reduce OWB biomass 

pastures, or in previously tilled areas. fill materials for OWB seed; and fuel load, graze in 

riparian 

corridors Use late season, long-term 

mowing to reduce OWB 

growth in spring. Since 

movement of seed can 

increase infestations along 

ROWs, do not mow once 

OWB flowering heads have 

started to form. 

use pellets for horses in 

backcountry areas. 

Avoid driving vehicles and 

equipment through infested 

areas. Decontamination 

procedures should be 

implemented if travel through 

these areas is necessary. 

the spring when OWBs 

may be more palatable 

or graze standing residue 

in the fall-winter. Use a 

protein supplement with 

fall or winter grazing. 

Classical biocontrol 

agents are unavailable. 

Use truck or tractor-mounted 

spraying equipment to

broadcast treat. In areas 

difficult to access, an ATVmounted sprayer or backpack 

unit may be the most 

practical application method. 

Wash underneath vehicle after 

application to prevent seed 

spread. 

Burning used alone is not Where feasible, consider 

recommended as it will reseeding areas with native 

likely result in increased grasses or other desirable 

OWB densities; consider plant species following OWB 

combining burning with control actions. 

herbicide spraying. 

Wilderness, Hand pulling or digging same as above same as above 

other natural may aid in control. Pull 

areas, and/or when soil is moist and 

small remove as much root stock 

infestations as possible; wear gloves for 

pulling. 

Use backpack or hand-held 

sprayers. If allowed, vehicle 

sprayers may be used to 

broadcast spray thick OWB 

stands. Wash underneath 

vehicle after application to 

prevent seed spread. 

*Choice of a particular management option must be in compliance with existing regulations for the land resource.

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Physical Control 

Physical methods used to control OWBs normally have to 

be repeated and must be timed properly with seedhead 

formation to be effective. Mowing and burning used alone 

do not control OWBs and discontinuing them can reestablish OWB densities to pretreatment levels or worse. 

Thus, an integrated approach that combines mowing or 

burning with herbicide application should be used. 

Manual Methods 

Hand removal – For isolated or patchy plants, hand pulling 

or digging to remove top growth and roots are the most 

effective techniques. Hand removal of OWBs can be 

complicated as these species can form mats. Manual 

methods may be combined with herbicide application when 

OWB populations are relatively small or isolated. 

Mechanical Methods 

Note – If using machinery to manage OWBs, the equipment 

should be cleaned after use in infested areas to prevent 

transfer of seed into un-infested areas. 

Tillage – Tillage with a disk or plow may be used to remove 

OWBs from previously tilled areas such as old cropland; 

however, any newly tilled area will need to be planted with 

desirable vegetation. Better results with tillage may be 

achieved when conditions are dry enough to desiccate OWB 

root fragments. Repeated shallow tillage with implements 

such as a rotary or disc harrow may prevent deeply 

embedded seeds from coming to the soil surface for 

possible germination. Nonetheless, tillage without follow-up 

control measures can increase OWB densities by breaking 

up root masses and scattering the fragments. It also exposes 

bare soil, which can become infested by OWBs. See 

Integrated Control Methods at the end of this section for 

information on integrated approaches using tillage. 

Mowing – Mowing along ROWs has the potential to spread 

OWB seed and can lead to OWB dominance within ROWs. 

Therefore, infested ROWs and other transport corridors 

should not be mowed once OWB flowering heads have 

started to form, as this will move seed into un-infested areas. 

However, one study conducted in Oklahoma found that 

sustained mowing done annually in September can reduce 

OWB cover on a long-term basis as compared to un-mown 

areas or areas mowed in March or June. Mowing is more 

effective if combined with pre or post-herbicide treatments. 

Prescribed Fire 

OWBs rapidly recover after fire and may return at greater 

densities than before. Thus, burning is not recommended as a 

single or stand-alone control method. As compared to 

mowing, burning is better able to reduce OWB cover. 

Prescribed fire applied past the boot stage but prior to full 

seed production has shown the greatest potential for 

reducing OWB cover. 

Cultural Control 

To prevent OWB seed movement, sanitary measures for 

vehicles, equipment, and livestock should be implemented. 

Only clean vehicles and equipment should be allowed to 

enter un-infested areas. Seed and materials used for planting,

mulch, animal forage, or fill should be tested for presence of 

OWB seed; pellets may be used for horses in backcountry

areas. 

Public education about the use of non-native grasses, such as 

OWBs, and their impacts on ecosystems is essential for 

changing seeding practices. Agencies and landowners should 

collaborate in promoting use of native or other desirable 

species rather than OWBs for reseeding areas disturbed by 

mining, fire, overgrazing, or road construction. In the 

Southwest, species such as Arizona cottontop (Digitaria 

californica), sideoats grama (Bouteloua curtipendula), 

sprucetop grama (Bouteloua chondrosioides), plains 

bristlegrass (Setaria macrostachya), and other native species 

adapted to relatively lower elevations may be considered. 

Biological Control 

Grazing 

By itself, grazing is inadequate to eradicate or control 

OWBs as these species are highly tolerant of close grazing 

or defoliation. OWBs are palatable when young and may 

have equal or greater forage quality in the early growing 

season as compared to some native species. However, OWB 

plants generally mature more quickly than most native

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warm-season grasses and correspondingly become less 

palatable. Burning and mowing old vegetation can increase 

OWB palatability, and some cultivars may be more palatable 

to livestock than others.

Although OWBs are usually avoided by grazing animals in 

favor of native vegetation during periods of adequate 

moisture, they can be highly selected by grazers during 

drought periods. OWBs retain green leaf material longer 

than some native species at the onset of drought, which 

allows them to recuperate more rapidly when precipitation

eventually returns to normal levels. 

Stocking rates that do not account for areas occupied by 

OWBs may inadvertently overutilize native vegetation. 

Therefore, stocking may need to be adjusted to favor 

native grasses. Continuous, intensive grazing should 

generally be used only on lands close to a full monoculture 

of OWBs; otherwise, native plants will probably be overutilized. 

Intensive grazing of OWBs with cattle in the early part of 

the growing season may enhance grazing use. Fall grazing 

of OWBs using a deferred-rest, rotational grazing system 

may also provide better utilization. However, additional 

protein is required since protein and nutritional values for 

OWBs decline significantly in the fall and winter. Protein

supplements in granular, block, crystal, or liquid form can 

be used in conjunction with grazing dead OWB plants. 

Protein supplements can increase palatability, % crude 

protein, and total digestible nutrients (TDN) in fall-winter 

diets. Although these protein sources can be fed in 

containers, some forms of protein supplement may be placed 

directly on patches of standing dead OWBs. 

Treatments that reduce standing dead material such as

mowing or burning may encourage greater utilization of 

OWBs by grazing animals. A high stocking rate with grazing 

animals may remove dead material, which will stimulate 

new OWB growth that can be treated by a foliar herbicide. 

Trampling by cattle can be used to break down clumps and 

mounds of OWBs if the cattle are concentrated within a

relatively small area. To concentrate animals, a temporary 

electric fence that is periodically moved to areas needing

treatment may be used. Placement of protein, mineral, or salt 

in troughs, tanks, tubs, or blocks within areas of standing 

dead OWBs and then eventually moving these feedstuff 

materials to other affected sites can provide sufficient 

trampling for reduction of clumps and mounds while also 

benefitting livestock distribution. 

It is not known whether OWB seed ingested by grazing 

animals remains viable after passing through the animal; 

however, it would be prudent to isolate animals in a drylot 

and avoid moving them directly from OWB-infested 

pastures into un-infested areas for at least 7 days to allow 

passage of any possible viable seed. 

Classical Biological Control 

At present, no known organisms or pathogens (insects, 

fungi, viruses, etc.) are present in the U.S. that are natural 

enemies or biocontrol agents for either OWB species. 

Chemical Control 

The primary herbicides used for OWB control are 

glyphosate and imazapyr (Table 2). Both herbicides will 

provide bluestem control when properly applied; however, 

the two herbicides are non-selective and will impact nontarget species. Therefore, precautionary measures should 

be taken if non-target plants (including woody species) 

need to be protected. Repeated use of the same herbicide 

on OWB infestations could lead to herbicide resistance; 

thus, the two herbicides should be alternated in their use. 

Glyphosate will kill or control most other plants 

intermixed with OWBs, while imazapyr allows some 

native tallgrasses to survive and persist after application. 

Studies done in the Midwest have shown that Western 

wheatgrass (Pascopyrum smithii), tall dropseed 

(Sporobolus compositus), sideoats grama, and western 

ragweed (Ambrosia psilostachya) had the best survival 

after glyphosate treatments; however, the herbicide is very 

damaging to most mid and tall grasses. Big bluestem 

(Andropogon gerardi), little bluestem (Schizachyrium 

scoparium), Indiangrass (Sorghastrum nutans), and 

sideoats grama were found in the Midwestern studies to be 

tolerant of some imazapyr treatments, and they may 

increase in density following OWB removal.

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Table 2. Herbicide recommendations 

Common 

Chemical 

Name (active 

ingredient) 

Product 

Example1 

Broadcast 

Treatment 

(rate per 

acre) 

Spot 

Treatment 

(spray 

solution)2 

Time of 

Application Remarks 

Glyphosate – 

single 

application 

Roundup, 

Roundup 

Ultra, 

Rodeo, 

Accord 

[others 

available] 

2-3 lbs per

acre

1.5% of a 5.5 lb 

per gallon 

product 

or 

2.0% of a 4 lb 

per gallon 

product 

Favorable growing 

conditions and 

adequate moisture 

should be present; 

apply when OWBs are 

in boot stage or any 

time prior to seed 

production while 

leaves are green and 

plant is actively 

growing. 

Glyphosate is formulated as a product 

with either 2 lb, 4 lb, or 5.5 lb active 

ingredient per gallon. Certain brands 

require addition of a non-ionic surfactant 

(NIS). Read label carefully to mix the 

proper rate of application. Do not add 

ammonium sulfate when spraying 

rangelands. Also, consider tank mixes of 

both glyphosate and imazapyr for 

increased control. See herbicide label for 

details. 

Although immobile in soil, glyphosate 

is a non-selective amino acid inhibitor; 

its spray drift can damage non-target 

plants, including forbs and woody 

species. 

Glyphosate – 

split application 

same as 

above 

1-2 lbs per

acre

same as above First application is at the 

5-leaf stage. Second

application is 8 weeks 

later.

Imazapyr – 

single 

application 

Habitat, 

Arsenal 

[others 

available] 

0.5 lbs per 

acre 

1.0% of a 2 lb 

per gallon 

product 

Favorable growing 

conditions and adequate 

moisture should be 

present; apply when 

OWBs are in boot stage 

or any time prior to seed 

production while leaves 

are green and plant is 

actively growing. 

Herbicidal activity may be slow, and the 

extent of control may not be evident until 

the following growing season. 

Imazapyr is a non-selective amino 

acid inhibitor. In addition to spray 

drift, non-target plants may also be 

killed or injured by imazapyr 

through runoff, residue movement 

in soil, or root exudates from treated 

plants. Imazapyr – same as 0.25 lbs per same as above 

split application above acre 

First application is at the 

5-leaf stage. Second

application is 8 weeks 

later.

1 Trade names for products are provided for example purposes only, and other products with the same active ingredient(s) may be available. Individual 

product labels should be examined for specific information and appropriate use with OWBs. 

2 Spray solution is the herbicide/water ratio in a spray mix that may be used for spot treatment with backpack or hand-held sprayers. The amount of product 

applied during an annual growing season must not exceed the maximum application rate per acre as specified by the product label – refer to the product 

label for the site type and application. 

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Aquatically approved herbicide formulations and 

surfactants of glyphosate and imazapyr must be used in 

or near water. Each herbicide product has different 

requirements and restrictions. Therefore, label 

instructions should be carefully followed when mixing 

and applying any herbicide. 

Herbicide Application 

Applying herbicide to OWBs as a single treatment 

without follow-up can be ineffective or worse than not 

using herbicide at all. Following initial glyphosate 

treatment, OWB seedlings can continue to emerge for 

as long as 3 years. In many instances, OWBs have been 

observed to recover within 1 year after treatment (YAT) 

or 2 YAT due to emergence of new seedlings from the 

soil seed bank and from basal buds of mature plants that 

escaped herbicide treatment. 

OWB control on a short-term basis has been successful 

with both single and split applications of glyphosate 

and imazapyr during the growing season. Whether 

applied as a single dose or as split applications, both

herbicides typically give similar OWB control. 

Mixtures of imazapyr and glyphosate can also provide 

short-term control. Under dry conditions, greater rates 

of herbicide are required to achieve the same control as

lower rates of herbicide used during favorable growing 

conditions, especially with glyphosate. 

For split applications of glyphosate using a broadcast 

treatment, apply 1-2 lb/acre at the 5-leaf stage and then 

treat again at the same rate eight weeks later. With 

favorable growing conditions and adequate moisture, a 

single dose of 2-3 lb/acre glyphosate may be broadcast 

applied as an alternative treatment when OWB plants 

are in the boot stage. Infestations can also be treated 

with a single dose of glyphosate at 2-3 lb/acre at any 

time late in the season prior to seed production if leaves 

remain green and the plants are still growing or 

photosynthesizing well. Single dose glyphosate 

applications in late season have been found to be more 

effective as compared to early season applications. 

Alternatively, imazapyr can be broadcast applied in a 

split application at 0.25 lb/acre at the 5-leaf stage and 

then again at the same rate eight weeks later. Imazapyr 

may also be applied in a single dose at a rate of 0.5 lb/

acre when the plant is in the boot stage or later prior to 

seed production, as long as the plant is green and 

favorable growing conditions exist. 

For herbicide control of individual plants or small 

patches with a handheld or backpack sprayer, apply a 

1.5% solution of a 5.5 lb glyphosate/gallon product or 

a 2.0% solution of a 4 lb glyphosate/gallon product. 

Alternatively, a 1.0% solution of a 2 lb imazapyr/gallon 

product can be applied. 

Application Techniques 

To limit impacts to desirable plants during herbicide 

applications, direct spray of OWBs from a backpack or 

hand-held sprayer is preferable to broadcast treatment. 

Enough spray should be used to wet leaves but avoid 

dripping from the plant. Adding a blue or red dye to the 

solution will aid in identifying treated plants. A team of 

applicators walking together side-by-side (about 10 feet 

apart) is an effective way to spray a defined area 

systematically. This method is particularly effective for 

treating relatively small, less dense infestations. 

A ropewick application method may provide modest 

OWB control. Ropewick applicators can be hand-held 

or else towed or mounted on a tractor, ATV, or UTV. 

Ropewick applications do not control new or young 

seedlings, but they may control well-established plants 

with a taller canopy. If native species are mown or 

heavily grazed first, the ropewick can be set lower and 

made more effective. According to one Midwest study, 

a ropewick application using glyphosate and water in a 

50:50 ratio on a volume to volume basis provided an 

average of 65% control in the third season following 

annual ropewick applications made in the first 2 years. 

For large infestations, it may be more practical to use a 

boomless or conventional boom sprayer that is 

mounted on a vehicle (ATV, UTV, truck, or tractor) or 

else is towed. Any equipment (including backpack 

sprayers) used to spray herbicide should be calibrated. 

See the Suggested Web Sites subsection at the end of 

this document for calibration information. Before 

8 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

spraying, always consider the need to reseed with desirable 

native grasses after herbicide application.

Integrated Control Methods

Grazing, mowing, or burning OWB infestations—applied 

singly or in combination—do not adequately control OWBs. 

The timing and frequency of these treatments may actually 

increase OWB vigor relative to native plants and make 

OWBs even more competitive. However, use of these 

treatments either prior to herbicide application or between 

split herbicide applications greatly increases herbicide 

effectiveness on OWBs, as the new green foliage arising 

from the treatment will potentially enhance total herbicide 

uptake and translocation. Herbicide label restrictions for 

grazing should be followed.

Tillage 

If OWBs are present in tillable areas such as previously 

cropped areas, then plowing or deep disk tillage followed by 

treatment of new OWB plants with glyphosate, imazapyr, or 

a mixture of the two can greatly reduce OWB cover. Followup treatments of emergent OWBs on the fallow land and 

eventual reseeding with desirable vegetation are required to 

keep OWBs from re-populating. Conducting tillage and 

seeding of an annual crop such as winter wheat for 3 or more 

consecutive years should also provide significant OWB 

control. Reseeding to native grasses and forbs may then be 

possible if coupled with several years of herbicide 

treatments to control new OWB seedlings and plants that 

escaped previous treatment. 

Management Strategies

In the Southwest, seeding of OWBs has historically been 

limited to ROWs, CRP lands, and drought-affected 

rangelands. OWB species are not currently recognized as a 

problem in Arizona or New Mexico as they are not yet 

broadly established in pastures and native grasslands of 

either State. However, OWB infestations are expected to 

continue expanding and eventually become a major threat 

similar to the Midwest where OWBs have become highly 

invasive across grassland areas. Success in keeping OWBs 

from becoming a more widespread and expensive problem 

will necessitate stakeholders (agencies, landowners, etc.) 

working together collaboratively, particularly in managing 

pathways (road systems, waterways, etc.) by which OWBs 

can invade. A major emphasis should be to maintain or 

restore diversity and resiliency of native plant 

communities. 

Control and restoration efforts for OWBs require longterm planning, sustained management, and follow-up

monitoring. To protect pastures and native grasslands,

eradication or at least containment should be employed 

against OWB infestations wherever feasible. Efforts to 

control OWBs in ROWs should especially be emphasized

and coordinated with State and county highway

departments. Satellite populations and perimeter edges of 

large infestations may be treated first with the entire 

infestation scheduled to be eradicated, contained, and/or at 

least reduced in a series of steps over a period of several 

years. 

For lands where eradication or containment of OWBs are 

no longer practicable due to widespread infestations, 

management efforts should focus on (1) slowing their 

spread if possible and (2) reducing OWB dominance in 

heavily infested areas to increase plant and/or faunal 

diversity. However, it may be more cost-effective in some 

situations to put control efforts toward protecting areas that 

remain free of OWBs rather than causing disturbance in 

areas that are already extensively infested by them. 

In most cases, at least 3 or more consecutive seasons of 

field treatments will be necessary to eliminate or 

substantially reduce OWB infestations and soil seedbanks 

following initial treatment. Treated areas will require 

monitoring and likely retreatment to control newly 

emerging seedlings and recovering patches of OWBs. 

Since it is useless to treat an area only one time without 

retreatment, sufficient resources must be allocated for the 

area where control is attempted. After initial treatment, it 

is essential that resources are available to respray or retreat 

the treated area as necessary. 

9 
 

 

 

 

 

 

 

 

 

 

References and Further 

Information 

CABI. 2018. Bothriochloa ischaemum (yellow bluestem) 

[original text by G. Wilson, 2015]. In: Invasive 

Species Compendium. Wallingford, UK: CAB 

International. www.cabi.org/isc. 

Casey, J. 2014. Timing and intensity of steer use on Old 

World bluestem (Bothriochloa ischaemum) and 

blue grama (Bouteloua gracilis) in southern mixed 

grass prairie. Fort Hays State Univ., M.S. Thesis. 

Clayton, M.K., J.L. Foster, K.C. McCuistion, T.W. 

Teinert, and M.M. Lesak. 2017. Introduced 

bluestem grasses: management on native lands. 

Texas Agrilife Extension Service. ERM-036. 

Coleman, S.W., C.M. Taliaferro, and R.J. Tyrl. 2004. Old 

World bluestems. p. 909-936. In L.E. Moser et al. 

(ed.) Warm-season (C4) grasses. Agronomy 

Monographs 45. ASA, CSSA, and SSSA, Madison, 

WI. 

Dee, J.R., S.M. Thomas, S.D. Thompson, and M.W. 

Palmer. 2016. Long-term late season mowing 

maintains diversity in southern US tallgrass prairie 

invaded by Bothriochloa ischaemum. Applied 

Vegetation Science 19: 442–453. 

Elmore, D., L. Goodman, K.R. Hickman, and K. Alspach. 

Options for Expiring Conservation Reserve 

Program (CRP) Land (NREM-9016). 

Fulbright, T.E., K.R. Hickman, and D.G. Hewitt. 2013. 

Exotic grass invasion and wildlife abundance and 

diversity, south-central United States. Wildlife 

Society Bulletin 37(3):503–509. 

Gabbard, B.L., and N.L. Fowler. 2007. Wide ecological 

amplitude of a diversity-reducing invasive grass. 

Biological Invasions 9:149–160. 

George, A.D., T.J. O’Connell, K.R. Hickman and D.M. 

Leslie, Jr. 2013. Food availability in exotic 

grasslands: a potential mechanism for depauperate 

breeding assemblages. The Wilson Journal of 

Ornithology 125:526-533. 

Greer, M.J., G.W.T. Wilson, K.R. Hickman, and S.M. 

Wilson. 2014. Experimental evidence that invasive 

grasses use allelopathic biochemical as a potential 

mechanism for invasion: chemical warfare in 

nature. Plant and Soil 385:165-179. 

Harmoney, K.R. 2010. Rate and timing of glyphosate 

application to control Caucasian Old World 

bluestem (Bothriochloa bladhii). Invasive Plant 

Science and Management 3:310-314. 

Harmoney, K.R. 2016. Old world bluestem seedling 

emergence and vegetative cover following 

glyphosate treatment. Kansas Agricultural 

Experiment Station Research Reports: Vol. 2: Iss. 

2. https://doi.org/10.4148/2378-5977.1182

Harmoney, K.R. 2016. Ropewick application to control 

Old World bluestems. Kansas Agricultural 

Experiment Station Research Reports: Vol. 2: Iss. 

2. https://doi.org/10.4148/2378-5977.1183

Harmoney, K.R., and K.R. Hickman. 2012. Comparing 

morphological development and nutritive value of 

Caucasian Old World bluestem and native grasses. 

Online. Forage and Grazinglands doi:10.1094/FG2012-0127-01-RS. 

Harmoney, K.R., P.W. Stahlman, and K.R. Hickman. 

2004. Herbicide effects on established yellow Old 

World bluestem (Bothriochloa ischaemum). Weed 

Technology. 18:545-550. 

Harmoney, K.R., P.W. Stahlman, and K.R. Hickman. 

2007. Suppression of Caucasian Old World 

bluestem with split application of herbicides. Weed 

Technology 21:573-577. 

Hickman, K.R., G.H. Farley, R. Channell, and J.E. Steier. 

2006. Effects of Old World Bluestem 

(Bothriochloa ischaemum) on food availability and 

avian community composition within the mixedgrass prairie. The Southwestern Naturalist 51:524-

530. 

Mittlehauser, J.R., P.W. Barnes, and T.G. Barnes. 2011. 

Blackland prairie restoration in central Texas. 

Natural Areas Journal 31:226–233. 

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Pate, F.M., and W.E. Kunkle. 1989. Molasses-based feeds 

and their use as supplements for brood cows. 

Circular No. S-365. Florida Agric. Exp. Sta., Inst. 

Food Agric. Sci., Gainesville. 

Roberts, C. 2004. Caucasian Bluestem. University of 

Missouri Extension Guide No. G4674. Online 

at https://extension2.missouri.edu/g4674. 

Robertson, S. and K.R. Hickman. 2012. Aboveground 

plant community and seed bank composition along 

an invasion gradient. Plant Ecology 213:1461-

1475. 

Robertson, S., K.R. Hickman, K.R. Harmoney, and D.M. 

Leslie, Jr. 2013. Combining glyphosate with 

burning or mowing improves control of yellow 

bluestem (Bothriochloa ischaemum). Rangeland 

Ecology & Management: 66:376-381. 

Ruckman, E.M., S. Schwinning, and K.G. Lyons. 2012. 

Effects of phenology at burn time on post-fire 

recovery in an invasive C4 grass. Restoration 

Ecology 20:756-763. 

Ruffner, M.E., and T.G. Barnes. 2012. Evaluation of 

herbicide and disking to control invasive bluestems 

in a south Texas coastal prairie. Rangeland Ecology 

& Management 65:277-285. 

Schmidt, C.D. and K.R. Hickman. 2006. Stolon production 

in Caucasian Old world bluestem. Transactions of 

the Kansas Academy of Science. 109:74-76. 

Schmidt, C.D., K.R. Hickman, R. Channell, W.J. Stark, 

and K.R. Harmoney. 2008. Competitive ability of 

native grasses and non-native (Old World 

Bluestems; Bothriochloa spp.) grasses. Plant 

Ecology 197:69-80. 

Simmons, M.R., S. Windhager, P. Power, J. Lott, R.K. 

Lyons, and C. Schwope. 2007. Selective and nonselective control of invasive plants: effects of 

growing-season prescribed fire, herbicide, and 

mowing in two Texas prairies. Restoration Ecology 

15:662–669. 

Wilson, G.W.T., K.R. Hickman, M.M. Williamson. 2012. 

Invasive warm-season grasses reduce mycorrhizal 

root colonization and biomass production of native 

prairie grasses. Mycorrhiza 22:327-336. 

Photo Image Libraries 

Photo images of OWBs may be found: 

Flora of North America. Available at 

http://floranorthamerica.org/ 

SEINet Plants Database. Available at 

http://swbiodiversity.org/seinet/ 

Suggested Web Sites 

For information about calibrating spray equipment: 

KSU Research and Extension. Hand Sprayer Calibration 

Steps Worksheet. Available at 

http://www.bae.ksu.edu/faculty/wolf/PDF/MF2915-

Hand%20Sprayer.pdf 

NMSU Cooperative Extension Service Guide A613, Sprayer Calibration. Available 

at http://aces.nmsu.edu/pubs/_a/A613.pdf 

11 
 

 

 

For more information or 

other field guides, contact: 

USDA Forest Service 

Southwestern Region 

Forest Health 

333 Broadway Blvd., SE 

Albuquerque, NM 87102 

Or visit the Southwestern Region’s 

website for invasive species: 

http://www.fs.usda.gov/goto/r3/invasivespecies 

The use of trade or firm names in this publication is for reader 

information only and does not imply endorsement of any 

product or service by the U.S. Department of Agriculture. 

Recommendations made here for 

pesticide use are not obligatory, 

nor do they imply that discussed 

uses have been registered. All 

uses of pesticides must be 

registered by appropriate State 

and/or Federal agencies before 

they can be applied. 

CAUTION: Pesticides can be 

injurious to humans, domestic 

animals, desirable plants, and fish or other wildlife—if they 

are not handled or applied properly. Use all pesticides 

carefully and lawfully. Follow recommended practices for the 

disposal of surplus pesticides and pesticide containers.