Managing Sericea Lespedeza (Lespedeza cuneata) with Selective Herbicide

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This perennial invasive and exotic legume, also known as Chinese lespedeza, is a threat to native plants in rangeland, pastures, fields, parks, forests and meadows.

The plant was originally introduced from Japan and planted for soil improvements, wildlife forage and cover. Once established sericea lespedeza crowds out forage grasses and other native plants and develops extensive seed banks in the soil. Studies have shown the seeds may remain viable for 20 years or more. Left unchecked, small patches of sericea lespedeza quickly spread into larger, more difficult and expensive-to-manage infestations. Cultural practices, such as grazing and burning, do not adequately control sericea lespedeza. In fact, burning can enhance establishment by removing competition and scarifying the seeds to aid germination of new plants. Cattle will graze the plant early in the season. However, it quickly develops a woody stem, and its high tannin content makes it unpalatable. Because it is so aggressive, sericea lespedeza often crowds out plants, reducing biodiversity, resulting in monocultures ill-suited for providing adequate food and cover for birds and other wildlife. Sericea lespedeza has aggressively spread throughout Missouri, Oklahoma, eastern Kansas and southeastern Nebraska.

IDENTIFICATION

Sericea lespedeza is an erect, semi-woody plant ranging from 3 to 5 feet tall. The leaves are alternate along the stems and each leaf is divided into three smaller leaflets, about 1⁄2 to 1 inch long. Leaflets are covered with densely flattened hairs, producing a grayish-green or silver appearance. Near the axils of upper and median leaves, violet to purple flowers emerge in late summer singly or in clusters of two to four. Sericea spreads from root crowns and seeds. Seed dispersal is primarily by birds and animals and by haying infested fields.

COMMITMENT

Successful management of sericea lespedeza requires a long-term commitment because of the tenacious nature of the plant and high longevity of seed viability in the soil seed bank. The management goal should be to control the plants and prevent seed production until the seed in the soil are no longer viable. Infested areas should be monitored each year and new plants controlled. Establishing and maintaining a thick cover of desirable grasses through proper grazing management helps discourage new plant establishment and site invasion.

HERBICIDE APPLICATION TIMING

Early summer

Begin treatment when sericea lespedeza is a minimum of 8 inches tall (May to June). Treatment may continue as long as plants are not stressed through the summer. Use the higher labeled rate when the plants are larger than 18 inches.

Early fall

Treatment may continue through September when plants are actively growing. The higher labeled rate herbicides should be used late in the season due to the advanced growth stage of the plant.

HERBICIDES

PastureGard® HL (combination of triclopyr and fluroxypyr) at 0.75 to 1 pint per acre and Remedy® Ultra (triclopyr) at 1 to 1.5 pints per acre provides the most consistent control of sericea lespedeza across multiple application timings (Figure 1). The higher label rates tend to be more consistent than lower rates especially at August and September applications. Metsulfuron applied at later application timing provides good control of sericea lespedeza. Opensight® specialty herbicide (a combination of metsulfuron and aminopyrlid) provides good late season control when applied at 3 to 3.3 oz of product per acre. The use of a non-ionic surfactant is recommended for all treatments.

Figure 1:  Sericea lespedeza control one year after treatment with three herbicides applied at three application timings. Data is a summary of 21 field trials located in Oklahoma, Kansas, Nebraska, Illinois, and Georgia.

APPLICATION

Broadcast Application

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Adequate coverage is a key component of control for sericea lespedeza. For best results, apply 3 or more gallons per acre total spray volume by air or 10 to 20 gallons per acre total spray volume by ground equipment. Use of a nonionic surfactant at 1 to 2 quarts per 100 gallons of spray solution is recommended for all sericea lespedeza treatments.

Spot application

Mix 3 pints PastureGard HL or 4 to 6 quarts Remedy Ultra per 100 gallons of water (0.5 fl oz PastureGard HL or 1.5 to 2 fl oz Remedy Ultra per gallon of water).  Apply the spray uniformly and thoroughly wet the Sericea lespedeza foliage. Tank mixing of PastureGard HL with other herbicides is not required to control Sericea.

When using a backpack sprayer to treat small patches, adjust the spray tip to produce a higher volume spray, or install a flat spray tip such as a Teejet 2503 or 4004E. Backpack spraying is efficient for minor infestations and follow-up spot treatments. When treating by hand, be sure to spray all of the plants’ growing tips, spraying to wet at least 80 percent of the foliage.


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State restrictions on the sale and use of Opensight and Remedy Ultra apply. Consult the label before purchase or use for full details. Always read and follow label directions.

Opensight is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details.