Glenda Prieba – K-State Research and Extension
June is just around the corner, and sericea lespedeza (Lespedeza cuneata) will soon be in a rapid vegetative growth stage. Sericea lespedeza continues to be a major concern on rangeland, pasture, and some CRP acres in Kansas.
There are no known biological controls that can be effectively used on sericea lespedeza. However, grazing with goats can suppress sericea lespedeza stands and produce a saleable product. It takes 4 to 5 goats per acre (of sericea) to graze the plant heavily enough to eliminate seed production. Sheep will also graze sericea.
Frequent mowing will damage sericea lespedeza, but is also damaging to plants that might be growing/competing with sericea. A single mowing in mid- to late-July will eventually reduce stands of sericea lespedeza to some extent, but several years of mowing have not eliminated sericea in K-State work. A late-summer mowing will eliminate seed production most years.
Integration of mowing and herbicides can reduce stands of sericea lespedeza. Wait about 4 weeks after mowing before applying a herbicide. Herbicides applied at the correct time and under favorable environmental conditions can significantly reduce sericea lespedeza. Remedy Ultra (triclopyr) and PastureGard HL (triclopyr + fluroxypyr) can provide effective control when applied during June and into early July when the sericea plants are in a vegetative growth stage. Broadcast applications of Remedy Ultra at 1 to 1.5 pints/acre and PastureGard HL at 0.75 to 1.5 pints/acre should be applied in spray volumes of 10 to 20 gallons/acre. Do not apply Remedy Ultra and PastureGard HL on CRP land until the grasses are established. These herbicides are likely to damage broadleaf plants that have been planted in CRP. Products containing metsulfuron, such as Escort XP, Cimarron Plus, and Chaparral are generally more effective in the late summer when sericea lespedeza is actively blooming.
Recommended rates are 0.5 oz/acre of Escort XP, 0.625 oz/acre Cimarron Plus, and 2.5 to 3 oz/acre Chaparral. Use a non-ionic surfactant with all of these products.
For spot application, mix 0.5 fl oz PastureGard HL per gallon of water, use a 1 percent solution of Remedy Ultra in water, or 0.3 grams Escort XP per gallon of water. Aerial applications of these products should be done with a minimum spray volume of 3 gallons per acre. Higher volumes, e.g. 5 gallons per acre, will generally be more effective. Herbicide treatments will need to be repeated every 2 to 4 years to keep this invasive species in check. Initial treatments should reduce dense stands to the point where spot treatment can be used in future years.
Sericea lespedeza is a statewide noxious weed in Kansas and therefore needs to be controlled. It has a tremendous seed bank that helps reestablish stands. Left untreated, sericea lespedeza will dominate a site, greatly reducing forage production and species diversity. Persistence is needed to manage this species.