Sericea Lespedeza Control
Sericea lespedeza is an introduced perennial legume. It has erect, herbaceous to somewhat woody stems, standing 3 to 6 feet (0.8 2 meters) high, with many erect, leafy branches which are green to ashy in color. The compound leaves are composed of three leaflets, with leaflets varying in length from 1/4 to 1 inch (0.8 to 2.5 cm). The lower leaves have petioles, but the upper leaves are nearly sessile. The leaflets are much longer than wide, tapering to the base, and wider above the middle, narrowing abruptly to a small sharp point. Flowers are in clusters of mostly two to three in upper leaf axils. The corollas measure from 1/4 to 3/8 inch (7 to 9 mm) long and are a pale creamy-yellow with conspicuous purple or pink markings. Its myriads of fruits are oval, and up to 1/8 inch (3 mm) wide.
The pale creamy-yellow flowers are smaller than those of the native species, L. capitata and L. hirta, which also have cream-colored or yellowish flowers. The base of the standard (the upper petal of the flower) of sericea lespedeza has two broad purplish-rose-colored streaks on the inside of the center portion. The flowers of L. capitata and L. hirta occur in clusters of three to many (20 to 25), and the stem hairs of these two native species are spreading rather than being appressed to the stem as in sericea lespedeza.
Sericea lespedeza is a native of eastern Asia. It was first introduced in southern United States, and has now become naturalized from Maryland, Virginia, Tennessee, Missouri and Texas, north to Pennsylvania, Ohio, Michigan, Illinois and Oklahoma. The first recorded collection of sericea lespedeza in Missouri was made in 1938. It has been introduced into various areas as a soil cover for erosion control, for soil improvement, as food and cover for bobwhite quail, wild turkey and other wildlife, and to a lesser extent, for forage and hay.
Sericea lespedeza grows in woodlands, thickets, fields, prairies, disturbed open ground, borders of ponds and swamps, meadows, and especially along roadsides. It shows great resistance to summer drought and an ability to form a dense stand on sterile, steep or eroded slopes. Where it has invaded grasslands, sericea lespedeza is unpalatable compared to native species because of tannins present in its tissues.
Sericea lespedeza produces growth in the spring (mid to late April) from root crown buds at the base of last year's stems. Flowering begins in late July and can continue through October. As flowering progresses, root reserves are increased; a fact that has implications for use of translocated herbicides. Seeds are dispersed in the fall and are reported to remain viable for 20 or more years. Birds may play a role in seed dispersal, and certainly the species is spread by haying of infested fields.
Since its introduction into Missouri this century, sericea lespedeza has been widely planted and has become naturalized in most if not all Missouri counties. Numerous stands that are well established along roadways will continue to provide a source for spreading into surrounding, more natural habitats. Sericea lespedeza is designated a noxious weed in several Kansas counties.
Options available for control of sericea lespedeza include management, mechanical and chemical methods. There are no biological controls approved for sericea lespedeza at this time other than grazing.
Management: Rangelands can be managed to control sericea lespedeza by burning, grazing, and fertilization. Prescribed burning of native grass in the late spring followed by intensive grazing with mature cattle will increase utilization on sericea lespedeza. Grazing infested sites with sheep and goats will provide effective control. Pastures should be properly fertilized and grazed during April and May to reduce the occurrence of sericea lespedeza.
Fire has been used on non-rangeland infestations with some success. Late spring burns (May 15 to the end of June) may be effective if a fire will carry through the area at that time. Seed dormancy of sericea lespedeza can be broken by prescribed burning but resulting seedlings may be less viable. Breaking seed dormancy by burning may be preferable to allowing natural processes to accomplish this, since a persistent, long-lived seed bank may add new plants to the site for years to come. By forcing more seeds to germinate, following up with a mechanical or chemical treatment may have more long-term effects.
Mechanical: Root reserves of sericea lespedeza increase during flowering with a low point in the cycle at the flower bud stage. This low point provides a vulnerable stage at which to use mechanical control. Mowing in the flower bud stage for two to three consecutive years should reduce the vigor of sericea lespedeza.
- Rangeland control: Treatments containing triclopyr (e.g. Garlon 3A, Garlon 4) or metsulfuron (e.g. Ally, Escort) have been shown to be the most effective herbicides for sericea lespedeza control. Triclopyr at 1/2 pound acid equivalent per acre or metsulfuron at 0.3 ounces of product per acre can provide effective control of sericea lespedeza treated during the vegetative stage prior to branching or during flowering. Ground application of herbicides should be in 10 to 20 gallons of solution per acre to insure adequate coverage.
- Spot applications: Application of herbicides using backpack sprayers has been effective for small or scattered infestations. Foliar applications of glyphosate (tradename Roundup) have been effective at normal concentrations for foliar treatments. See herbicide label directions for appropriate concentrations. Glyphosate is effective from mid-June until seed set. When using any herbicide, precautions should be taken to avoid contacting non-target species. Do not spray so heavily that herbicide drips off the target species. The herbicide should be applied while backing away from the treated area to avoid contacting wet herbicide. By law, herbicides only may be applied as per label instructions.
Failed or Ineffective Practices
Prescribed burning alone may not be effective in controlling sericea lespedeza. Fire may actually enhance germinating of sericea lespedeza seed.
In rangeland situations, intensive, early stocking (doubling the normal stocking rate from May 1 to July 15 and then removing the livestock) with steers has not provided consistent utilization of sericea lespedeza.
2,4-D was not found to provide effective control for sericea lespedeza in rangeland applications.