Authors: TunyaLee Morisawa, Global Invasive Species Team, The Nature Conservancy
- Lespedeza bicolor is an upright semi-woody forb, 3-10 ft. (0.9-3 m) in height with many slender stems and arching branches.
- Leaves are elliptical, alternate, abundant and three-parted. Leaflets are oval with the lower surface lighter than the upper surface.
- Flowering occurs in the summer, when purple, pea-like flowers develop in clusters. Flowers are less than 0.5 in. (1.3 cm) long.
- The fruit are flat, indehiscent pods and contain one seed that measure up to 0.31 in. (8 mm) long.
- Ecological Threat
- Lespedeza bicolor is an extremely aggressive invader of open areas, forming dense thickets, which displace native vegetation. Native to Asia and introduced into the United States in the late 1800s, it has been widely planted for wildlife habitat, especially for northern bobwhite quail.
Lespedeza bicolor is a semi-woody perennial legume (Family Fabaceae) that is native to Japan. The shrub is shade-tolerant and planted as food for wildlife such as deer but more often for quail. Lespedeza bicolor may sometimes be used to prevent soil erosion. Purple flowers are present from mid to late summer and seed set is around the months of September to October. The shrub itself will grow to a height and spread of 2.4m (8 ft). The plant is frost intolerant, however, re-growth of shoots from the underground surviving root system will occur when the right environmental conditions return.
The biology of Lespedeza cuneata is similar to that of L. bicolor. Lespedeza cuneata is a threat to open meadows because it crowds out native plants and has an extensive seed bank; ensuring that it will be present for many years. Lespedeza cuneata is unpalatable to native wildlife due to large amounts of tannins in the leaves. More control information was found on this species and the information has been incorporated into this report because of the similar biology of L. cuneata and L. bicolor. Although the biology is similar L. bicolor is a shrub or subshrub and L. cuneata is an herb, sometimes with a woody base. Control options for Lespedeza include management, mechanical and chemical methods. No biological control methods were found in the literature.
Fire management of L. cuneata includes late spring burns to break seed dormancy. Using fire forces seeds to germinate, depleting the long-lived seed bank. Resulting seedlings may be less viable, therefore, burning followed by intensive grazing with mature cattle is recommended. Lespedeza bicolor growth was observed after burning, however, increased pasture utilization time (cutting and grazing) was linked to a decline in the coverage of the shrub.
For L. cuneata hand pulling has been found to be impractical due to an extensive root system. Mowing at the flower bud stage for 2-3 consecutive years may reduce plant vigor and prevent spread.
No information on herbicides for the control of L. bicolor was found, however, one paper did report that L. bicolor is tolerant to the herbicide Oust® (sulfometuron-methyl) at the rate of 2-4 oz. per acre. The Missouri Vegetation Management Manual for L. cuneata suggests the use of triclopyr (Garlon 3A®, Garlon 4®) or metsulfuron (Ally®, Escort®) for rangeland control. Triclopyr (0.09 kg acid equivalent/ha or 0.5 lbs acid equivalent/acre) or metsulfuron (4.1 g/ha or 0.3 oz/acre) applied during the vegetative stage prior to branching or during flowering can provide control. The use of a backpack sprayer for spot applications of 2,4-D amine or glyphosate (please see label for recommended rate) are effective from mid-June until seed set. A web site listed Clopyralid (0.5%) as a control measures for L. cuneata. However, Triclopyr and Clopyralid should not be used in wet areas or near streams. 2,4-D in rangeland applications did not provide adequate control.
- Gucker, Corey L. 2010. Lespedeza bicolor, Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory
- Texas Invasive Plant and Pest Council
- Flora of China, www.eFloras.org
- North Carolina State University
- USDA NRCS PLANTS
- USDA ARS GRIN