Sericea Lespedeza – What? Why? How? When?

by R. Dwayne Rice, Rangeland Management Specialist
Natural Resources Conservation Service
Salina, Kansas

What is Sericea Lespedeza?

If you own or manage native range, pasture, or Conservation Reserve Program (CRP) acres planted to grass in Kansas what you don’t know could financially harm you, or at least wreck your profit margin. Sericea Lespedeza (Sericea), Lespedeza cuneata, more commonly known as Chinese bushclover, or a long string of unprintable superlatives, was labeled in Kansas as a noxious invasive weed in 1990. While other surrounding states still recognize Sericea as an agricultural crop or an introduced hayland species, Kansas and several of the more northern and western states see it as an ecological and economical nightmare in native rangeland.

Sericea lespedeza was first tested in North Carolina in 1896. It was intentionally planted in Kansas for erosion control, wildlife habitat, and as a forage crop as early as the 1900’s and again in the 1930’s. Sericea is a perennial, drought resistant, legume that each year forms somewhat shrubby erect stems from a base crown or caudex. Forage quality of Sericea is relatively low due to high tannin levels which reduce protein digestibility in cattle.

Why is controlling this plant so important?

It wreaks havoc on native rangeland pastures by invading and crowding out the more desirable and productive native plant species. A typical rangeland pasture in the Flint Hills region will contain around 120 native plant species. In the eastern third of Kansas, Sericea can become a mono-culture within a very few years if left unchecked. Forage production for livestock drops significantly as the amount of Sericea increases reducing a rancher’s economic income. Forb populations plummet, reducing plant and animal biodiversity. Sericea also changes the hydrologic cycle making it more difficult for the native plant species to compete for soil moisture. Even after the Sericea is controlled, native species are slow to re-establish. The best pastures in the state, even under good management regimes, are under threat of invasion. In fact, Sericea thrives under some management practices such as spring burning.

Sericea, while relatively slow to establish, is extremely difficult and expensive, if not impossible, to control once it is established and has been allowed to persist long enough to produce seed. Mature Sericea plants have been known to produce over 1,000 viable seeds per year per stem. These seeds can remain dormant for 15 to 20 years making control a long, drawn out process. The seeds of Sericea are also fairly easily transported by hay, livestock, wildlife, machinery, vehicles, and water. Since the seeds float, water transportation may be the fastest and most extensive mode of travel for Sericea.

How do you control Sericea?

Currently herbicides are the only reliable technological control method for Sericea. According to research and field trials, herbicides that contain triclopyr (Remedy) have shown relatively good control early in the summer before bloom while herbicides that contain metsulfuron (Escort) work better later in the season when the plants are blooming. Several years of data from Kansas State University research has shown some positive benefits in cultural control through livestock grazing. While cattle have a difficult time digesting the protein in Sericea forage, goats naturally secrete an enzyme in their saliva that separates the tannin from the protein. A feed additive, delivered to cattle through a grain, protein, or mineral carrier, may offer some hope for a cultural control method using cattle and increase the amount of Sericea selected in the diet. Research being conducted at Emporia State University has shown webworms to be effective at reducing seed production of mature Sericea plants. However, winter survival of adequate webworm populations has limited this biological control method to date. Scientists are concerned that until there is a well-rounded cultural (grazing), biological (web-worms), and technological (herbicides) approach to controlling this non-native noxious weed, Sericea will continue to invade into healthy rangeland at a staggering pace.

When do you control Sericea?

Landowners are encouraged to inspect all rangeland, pastureland, and CRP acres in the late summer and fall when Sericea is more easily identified. Early detection is essential to economical control. Apply herbicides when the Sericea plants are actively growing and not stressed by drought. Applying 10-20 gallons of water per acre are necessary to ensure adequate herbicide coverage. Spring burning can also improve coverage and herbicide effectiveness by removing standing mulch and germinating Sericea seeds. Spot spraying individual Sericea plants reduces damage to desirable plants, reduces the potential for off-site drift, is more cost effective to scattered infestations, and reduces the amount of herbicide entering the ecological system.

Producers are also encouraged to keep hay that may contain viable seed from Sericea infested areas on the site where the hay was harvested. If hay has been moved off site and is suspected of containing Sericea seed, feed it in a small area that can be monitored for several years. Check the labels of grass seed and grass seed mixtures for the presence of Sericea prior to purchase. Do not move livestock in late summer from an infested pasture to a clean pasture as viable Sericea seed can pass through the intestinal tract of animals. CRP participants are responsible for detecting and controlling Sericea on their property.

It is imperative to the health and well being of Kansas grazing lands for landowners and operators to take an active role in controlling Sericea lespedeza across the state.

For more information about Sericea Lespedeza, please contact your county Natural Resources Conservation Service, conservation district, KSU Research and Extension, or Noxious Weed Office. Additional information can also be obtained from the Multi-State Sericea Lespedeza Work Group Web site at www.oznet.ksu.edu/sericea/.

For more information about NRCS programs, visit the Kansas NRCS Web site at www.ks.nrcs.usda.gov.

This article is also available in Microsoft Word format.

Sericea Lespedeza – What? Why? How? When? (DOC; 43 KB)

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Last Modified: 09/04/2008