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The dog days of summer are upon us! Compared with recent past summers, most of Missouri has received ample rainfall this summer. This is good news in many ways, but it also means that many invasive plants are thriving. Soils are now drier for some parts of the state, and growth of some invasives has slowed, which can affect how well they absorb herbicides. Hot weather can also affect herbicide absorption. Nonetheless, it is important to continue "seeking and treating" invasive plants on farms, in backyards, parks, commercial property, and native habitats.

One invasive that seems to have exploded in recent years is Johnson grass (Sorghum halepense), pictured above. This warm-season grass may be abundant along roadsides and fields, and may be hard to distinguish from desired grasses in garden beds or plantings, as in the prairie planting pictured above. Learn below how to identify and control this invasive grass, which is included on Missouri's Noxious Weed List, so it can't get the upper hand.

We hope you find the news and resources in this issue of the Missouri Invasive Plant Council's (MoIP's) State of Invasives useful, and, as always, please let us know your invasive plant-related questions, ideas, or concerns. Here is a summary of items in this issue:

–Outcome of 2024 Missouri Invasive Plant Bills

–2024 MoIP Callery Pear Buyback Event Summary

–September 27: Invasive Plant Workshop & Field Day in Texas County

–November 6: MoIP Webinar: Common General Use Herbicides & How They Relate to Aquatic Use Sites

–From the Natural Areas Association: Recent Advances in Herbicide Formulations & Application Techniques for Woody Invasive Plant Management

–Success Story: Kansas City WildLands Sites

–Missourians Making a Difference: Valarie Kurre

–Invasive to treat now: Johnson grass, Japanese hop, kudzu, and sericea lespedeza

–MoIP at the Missouri State Fair

Thank you for taking action to identify and control invasive plants!

Carol Davit, MoIP Chair

Matt Arndt, MoIP Vice Chair

Photo above of Johnson grass (Sorghum halepense) in a prairie planting by Carol Davit

The 2024 Missouri legislative session ended on May 17. Unfortunately, Missouri House Bill 2412 and Missouri Senate Bill 1281, to prohibit the sale of five invasive plants*, are now dead because they were not scheduled for votes on the House floor or the Senate floor.

While this is disappointing, it is not unusual. On a positive note, the House bill passed out of the House Conservation and Natural Resources Committee with a 9 to 1 vote, and the Senate bill passed out of the Senate Agriculture, Food Production, and Outdoor Resources Committee unanimously. Both bills generated much media coverage and overall awareness among Missourians about the threats that invasive plants pose to Missouri's native habitats, working lands, land management, and outdoor recreation.

MoIP advocated for the passage of these bills, with the MoIP Chair, Vice Chair, Council members, and other supporters providing testimony at public hearings. Many thanks to all who contacted Missouri state elected officials in support of HB 2412 and SB 1281.

MoIP will encourage the sponsors of the 2024 bills to sponsor similar bills in the 2025 legislative session and will be ready to provide input if requested. Stay tuned for updates.

*Burning bush (Euonymus alatus), pictured above, invading forest in Barry County; Callery pear (Pyrus calleryana and its cultivars, including Bradford and Chanticleer); climbing euonymus (Euonymus fortunei; also known as wintercreeper); Japanese honeysuckle (Lonicera japonica); and sericea lespedeza (Lespedeza cuneata). 

As a creative way to call attention to the threat that non-native, invasive Callery pear trees pose to Missouri, in 2019 MoIP launched the state’s—and perhaps the nation’s—first Callery Pear “BuyBack” program. This special event invited Missourians to cut down one or more Callery pear trees on their property, submit a photo of a cut-down tree, and receive a free native tree to plant. Since that time, MoIP has annually grown the program, continually expanding the number of cities hosting a BuyBack event.

On April 23, 2024, in partnership with Forest ReLeaf of Missouri, Forrest Keeling Nursery, and the Missouri Department of Conservation (MDC), MoIP organized Callery (Bradford) pear “buyback” events in 15 locations around the state. As participants picked up their free native trees, they also received information about the problem with invasive species, the benefits of native trees, and the importance of properly planting and caring for their new trees. A Grow Native! Resource Guide to Suppliers of Native Plant Products & Services was offered to participants as well, and, if requested, an “I removed my invasive Callery pear and planted a native tree instead” yard sign to let the participants’ neighbors know the importance of their landscaping change. A 2023 grant from the Richard King Mellon Foundation provided financial support for MoIP’s 2024 Callery Pear Buyback program.

The program, which began in Columbia and St. Louis, has expanded through the years to also include Cape Girardeau, Springfield, Joplin, Lebanon, Hannibal, Farmington, Kennett, Rolla, West Plains, Kirksville, and St. Joseph. Collectively, these locations gave away 630 trees, with any leftover trees planted at parks, schools, and other local places where the public and native species that depend on native trees can benefit from their presence for many decades to come.

In addition, thanks to a partnership with the organization Deep Roots KC, which has followed MoIP’s lead and organized its own BuyBack event in the Kansas City area in Missouri and Kansas, an additional 200 trees were given away. Since 2019, cities around the country have sought advice from MoIP on how to start their own Callery Pear BuyBack events.

For more information about the Pear Buyback program and the invasive Callery pear, visit the MoIP Callery Pear Buyback page.

The Scenic Rivers Invasive Species Partnership and MU Extension in Texas County are hosting this workshop at the Texas County Extension Office in Houston, Missouri, on Friday, September 27 from from 10:00 a.m. to 3:00 p.m. Registration is free and includes lunch. The workshop will cover classroom and field identification of common invasives that landowners may encounter on their properties. Workshop participants will also practice safe herbicide handling, mixing, and application. Register here.

With the ongoing challenge of controlling invasive plants in native habitats, along roadsides, on working lands, yards, around businesses, schools, and in parks, we can all use some good news.

In this new feature of State of Invasives, we bring you invasive plant control success stories. We hope our first one, below, brings some spring to your step as you carry your loppers, backpack sprayer, or other control tools to your work site. Many thanks to MoIP Associate and Kansas City WildLands Program Manager Hunter Moore for contributing the inaugural success story:

The Kansas City metro area is home to stunning landscapes, wide prairies, sunny woodlands, shaded forests, and rich wetlands. Bridging The Gap’s Kansas City WildLands (KCWL) program is a coalition of resource professionals, private conservation organizations, and conservation-minded citizens that works to preserve and restore the healthiest and most diverse of these remnant ecosystems in the area—public lands that are open for all to enjoy.

Kansas City WildLands has been battling invasive plants throughout the Kansas City metro area for 25+ years. Restoration is a tortoise and the hare situation—slow and steady often wins the race. By using a variety of management tools including volunteer outreach, prescribed fire, and cut-stump treatments, this year several remnant native ecosystems are really "showing out" after last year's efforts.

Enjoy the success story and photos here, and remember that what you do makes a difference!

Above, great spangled fritillary butterflies (Argynnis [Speyeria] cybele) feed on nectar from purple milkweed (Asclepias purpurascens) in an area cleared of bush honeysuckle. Photo by Hunter Moore

Join this MoIP online training session to deepen your understanding of the safe and effective application of herbicides in and near aquatic environments. Learn about the latest best practices, regulations, and environmental impacts to ensure your herbicide use supports both land and water health.

This webinar, presented by Lucas Madison, the Corteva land management specialist for Arkansas, Oklahoma, Missouri, and Iowa, will cover common active ingredients (and their associated brand names manufactured by several different companies) appropriate for application near water. These active ingredients represent a large portion of the herbicides used today in both retail and commercial settings, in pastures, and right-of-way applications. The presentation will cover how different formulations of active ingredients can impact performance, environmental fate, and user safety. The presentation will also cover toxicology as well as label and SDS navigation.

Don't miss this opportunity to enhance your expertise and protect our aquatic ecosystems!

Wednesday, November 6, 2024 at 4:00 p.m.

Free. Register here. The webinar will be about 45 minutes, followed by a question/answer session. The webinar will be recorded with a link to a recording of the sent to all registrants.

Managing invasive plants in areas of high native biodiversity can be challenging. The Natural Areas Association (NAA) serves scientists and practitioners focused on the management of ecologically significant natural landscapes with the intent to protect biodiversity for current and future generations.

To this end, NAA offers a variety of educational programs, including webinars to present new information on a wide variety of topics in natural areas conservation. By practitioners and for practitioners, these one-hour programs highlight emerging scientific discoveries, new methodologies, and best practices to protect biodiversity within ecologically significant landscapes.

One such NAA webinar that is free and available to all is via a recording: Recent Advances in Herbicide Formulations and Application Techniques for Woody Invasive Plant Management. It will likely be helpful for private landowners too!

Photo above of Valarie Kurre (read about her below!) treating sericea lespedeza by Daniel Dalton

Throughout Missouri, many individuals are making significant progress in the early detection and control of invasive plants. MoIP is pleased to highlight their efforts.

SRISP Coordinator Valarie Kurre took time out of her busy schedule to describe her work. Enjoy!

How long have you been with SRISP, and what are your primary responsibilities?

I am the Coordinator for the Scenic Rivers Invasive Species Partnership (SRISP) and have been in this position for almost three years. The SRISP is Missouri's first Cooperative Invasive Species Management Area (CISMA). CISMAs are partnerships of federal, state, and local government agencies, private landowners, and various interested groups that manage invasive species (or weeds) in a defined area. 

The SRISP was formed in south-central Missouri to establish a strong, cross-boundary, public-private partnership that inventories, monitors, controls, and prevents the spread of invasive species in a nine-county area in the southern Ozarks that includes the Eleven Point, Jack's Fork, and Current Rivers. Because the SRISP is a non-profit with signed agreements with state and federal agencies, the organization makes it easier for cross-boundary invasive plant work across multiple agency boundaries and even with private landowners. The SRISP also provides education and outreach about invasives to citizens across Missouri by attending events and conferences, hosting workshops, and assisting with invasive plant removal with its equipment-sharing program.

As the SRISP coordinator, I have many responsibilities. While running day-to-day operations, I also assist partners with invasive plant projects and coordination between partners. I represent the SRISP in various working groups, such as the Missouri Invasive Plant Council (MoIP) and the Mahan’s Creek Conservation Opportunity Area Working Group. Working with partners, I hosted landowner workshops on invasive plant ID and treatment, as well as herbicide application and safety. I also assist with invasive plant treatments when I’m not busy in the office. These projects range from treating county road rights-of-way to assisting landowners with invasive plant projects.

Read more

Photo above of Valarie Kurre by Chancellor Kurre

Not all invasive plants are most effectively treated at the same time of year, and treatment methods can differ according to the seasons. Here, we highlight several species to treat in summer. You can find treatment guidelines for many invasive plants other than those highlighted below at moinvasives.org. 

Note: Treatment methods may differ considerably if invasives are found in otherwise intact, highly biologically diverse areas, in disturbed areas/altered landscapes, or if invasives are found in or near water. When using chemicals to treat invasives, always read label instructions. In addition to the resources below, you may also find this table of invasive plant treatment methods for grasslands, from the Missouri Prairie Foundation, helpful.

Photos below by Carol Davit; Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org; MDC; Dan Tenaglia, Bugwood;

Johnson grass (Sorghum halepense) is flowering now in much of Missouri. This coarse, warm-season, perennial grass can reach 7 feet tall. It grows in dense clumps or nearly solid stands. Johnson grass was introduced into the United States as a forage crop, but became problematic not only to natural communities but also to agriculture. It invades riverbank communities and disturbed sites, particularly fallow fields and wooded edges, as well as native grasslands, where it can crowd out native species. Johnson grass is on the Missouri Noxious Weed List.

Johnson grass has a prominent white leaf mid-vein, a rounded stem base, and is virtually hairless. (Eastern gama grass [Tripsacum dactyloides], a native grass found on prairies and sometimes along roadsides, also has a white leaf mid-vein, but its stem bases are flattened). Also, eastern gama grass flowerheads are spikelike whereas those of Johnson grass are in a large, loosely branched panicles as shown above. Consult this Johnson grass vs native look-alikes document for more ID tips. 

Dense patches can be controlled by spraying the foliage with 2% glyphosate. Best results are obtained when glyphosate is applied to plants that are 18 inches tall to early flowering stage. Alternately, sulfosulfuon (Outrider), at a rate of 1 oz per 100 gallons of water, can be applied via foliar spray before flower stalks set seed. Consult this Missouri Department of Conservation Johnson Grass page for more information.

We featured this species in the spring issue of State of Invasives and are noting it again here as you can still treat it, now through fall. Japanese hop (Humulus japonicus) is an herbaceous annual vine. Native to eastern Asia, it was imported to the United States in the late 1800s for use in Asian medicine and as an ornamental vine. Within Missouri, Japanese hop is found most commonly in the Missouri and Mississippi river corridors, but it is increasing its range within certain floodplains. Japanese hop outcompetes established vegetation in sunny areas with exposed moist soil.

This sprawling, twining, climbing vine has opposite, palmately divided leaves that are rough to the touch. It has inconspicuous green flowers, with male and female flowers on separate plants. Female flowers are borne on a drooping cone-like structure with overlapping scales (called hops). The stems have short, sharp, downward-pointing prickles.

In areas with light infestation, manual removal can work well within moist soil in early spring when the root system is small. (You will need sturdy gloves to protect your skin from the prickles!) The entire root and plant must be removed and taken off-site to prevent regrowth. Repeated pulling should continue until dieback in fall when new plants cease to emerge.

In areas with heavier infestations, a pre-emergent herbicide containing sulfometuron methyl (Oust® XP) applied in mid-March generally causes minimal or no damage to other perennial vegetation, eliminating the need to rescue desirable vegetation from an established hop infestation. Application of a pre-emergent herbicide followed by a foliar application of glyphosate or metsulfuron applied prior to seed production (mid-April to August) may provide the most effective control. Subsequent applications will be necessary to control germinating plants throughout the season to prevent seed production.

See this Missouri Department of Conservation Japanese hop page for more information.

Sericea lespedeza (Lespedeza cuneata) is a perennial legume with herbaceous to somewhat woody stems, growing 3 to 6 feet tall, with many erect, leafy branches. Flowers, which bloom from July through October, are ¼ to ⅜ inch long and in clusters, the petals cream colored with purple or pink markings. Its myriad of seeds are borne in small oval pods that are up to ⅛ inch wide.

Leaves are green to ashy green with densely flattened hairs, compound with 3 leaflets each ¼ to 1 inch long.

Sericea lespedeza seed remains viable in the seed bank for many years. Prescribed burning stimulates sericea seed to sprout, and following up with a chemical treatment may speed up ridding soil of the seed. The most commonly used chemicals for treatment are a mixture of triclopyr and fluroxypyr (PastureGard) or triclopyr (Remedy) once plants are at least 12 inches tall. Later in the growing season, when plants are flowering until seed set, use metsulfuron (e.g., Ally, Escort, Cimarron).

Labeled use rates for the chemicals below can change as the growing season progresses, but are commonly applied at the following rates with surfactant added at .25-.5% solution: PastureGard - Spot spray at .5 oz per gallon of water or broadcast spray at .75 pints per acre / Remedy Ultra - Spot spray at 1.25 oz per gallon of water or broadcast spray at 1-2 pints per acre / Escort XP - Spot spray at 1 oz per 100 gallons of water or broadcast spray at .5-1 oz per acre. Always read and follow chemical labels.

Read more in this Missouri Department of Conservation Sericea Lespedeza Fact Sheet. Note: Do not confuse sericea lespedeza with native slender lespedeza (Lespedeza virginiana), which does not have the distinct “fishbone-like” leaf venation pattern that sericea lespedeza has. Also, the native has light to dark pink flowers (not cream-colored petals with purplish markings, that sericea has, as shown in the inset photo above).

Kudzu (Pueraria montana) is a climbing, semi-woody, perennial vine in the legume family. In Missouri, kudzu was planted along highways to control erosion mostly in select southern counties, mostly along highways and often draping over trees and other vegetation. It may be confused with other vines like native grape vines. See ID details here. 

Kudzu grows well under a wide range of conditions and in most soil types, except for saturated soils. Preferred habitats are forest edges, abandoned fields, roadsides, and disturbed areas, where sunlight is abundant.

Efforts to control kudzu infestations include cutting, grazing, digging, disking, prescribed burning, and herbicide application. Roots of mature plants grow too deeply to be affected by freezing. Burning will kill only the very young plants. Young colonies can be eradicated in three to four years if roots are dug, or if plants are overgrazed or persistently and repeatedly cut back during the hottest temperatures of summer.

Kudzu infestations four years old or more may cover an acre or more with older roots that are too deep for manual removal. Patches more than 10 years old will typically have root crowns (woody knots at the soil surface where stems originate) over 5 cm (2.0 in) in diameter. In these situations, mowing, disking, grazing or burning are unlikely to have much effect. A prescribed burn in March before herbicide treatment will kill the smallest plants and sever draping vines, leaving roots and new growth a better chance for exposure to chemicals. This is an opportune time to mark the largest roots as well as any hazards in the area slated for treatment. Old roots need heavier herbicide application than young ones. Best results from herbicides are applied in late summer when flowers appear and nutrients are being actively transported to roots.

Roundup and Rodeo (glyphosate), are the safest herbicides for use in residential and environmentally sensitive areas. Both are nonselective, foliar-applied herbicides, with Rodeo being licensed for use over water. Many years of persistent treatment will be necessary to achieve eradication.

Transline (clopyralid) is readily absorbed by foliage and roots and is translocated throughout the plant. This herbicide is targeted to three plant families: legumes, smartweeds, and composites. At 21 ounces per acre, Transline has the benefit that it may be used near trees, grasses, and dicots other than the three target families, without damaging them. Transline has not proven effective in eradicating older infestations of kudzu, but may be helpful in treating young patches and in controlling the spread of older plants.

Learn more from this Missouri Department of Conservation Kudzu Fact Sheet.

Many thanks to Conservation Projects Associate Lilly Germeroth and Prairie Stewardship Assistant Clifford Barratt, both with the Missouri Prairie Foundation, for staffing a MoIP booth at the Missouri State Fair on August 9, which was Missouri Invasive Species day at the fair. Along with representatives from other agencies and groups working to control invasive plant and animal species in Missouri, Lilly and Clifford shared MoIP fact sheets with Missouri State Fair visitors and answered questions about invasive plant identification and control.

State of Invasives aims to:

• Provide useful information to you/the leaders of your organization, agency, or business to help you recognize and control invasive plants and reduce their negative impacts, introduce you to our work, explain the challenges of invasive plants, and make the case for bold action and how this will benefit Missouri and Missourians. 

• Share talking points that you can use when communicating about invasive plant detection and control within your agency, business, or organization, and to your customers or stakeholders. 

• Empower you and your audiences to recognize invasive plants and take action—around your office building, behind your parking lot, on your back 40, right of way, back yard, around your crop field, or on any other land you or your group owns or manages. Our MoIP Video: A Landowner Tour is one of MoIP's many useful resources.

We hope the information in this enewsletter is helpful, and we’d like to hear from you. What questions or ideas do you have? Would you like to share the invasive plant action you or your organization or business are taking with us? If so, contact us at info@moinvasives.org.