KSN - Vol. 56, No 1 - Summer 2009Volume 56 - Summer 2009

Sericea Lespedeza in Kansas


ABOUT THIS ISSUE

ISSN: 0022-877X

Published by Emporia State University

Prepared and Issued by The Department of Biological Sciences

Editor: John Richard Schrock

Editorial Committee: Tom Eddy, R. Brent Thomas, William Jensen, Marshall Sundberg, Eric Yang

Mailing: Roger Ferguson

Circulation (this issue): 10,000

Press Run: 15,000

Press Composition: John Decker

Printed by: ESU Printing Services

Online edition by: Terri Weast

The Kansas School Naturalist is sent free of charge and upon request to teachers, school administrators, public and school librarians, youth leaders, conservationists, and others interested in natural history and nature education. Back issues, some photocopied, are sent for one dollar postage/handling charge per issue. A back issue list is sent free upon request. The Kansas School Naturalist is sent by third class mail to all U.S. zipcodes, and first class to all other countries. The Kansas School Naturalist is published by Emporia State University. Editor: John Richard Schrock, Department of Biological Sciences. Third class postage paid at Emporia, Kansas. Address all correspondence to Kansas School Naturalist, Department of Biological Sciences, Box 4050, Emporia State University, Emporia, KS 66801-5087. Opinions and perspectives expressed are those of the authors and/or editor and do not reflect the official position or endorsement of ESU. The KSN is listed in Ulrich’s International Periodicals Directory, indexed in Wildlife Review/Fisheries Review, and appropriate issues are indexed in the Zoological Record. Publication and distribution of this issue of the Kansas School Naturalist was partially underwritten by contributions from readers like you. Librarians Note: The KSN is an irregular publication issued from one to four times per year.

Photos: The two photos of the caterpillars - both on page 11 - were courtesy of Greg Sievert.  


 Picture - Melissa A. RossowAuthors: Melissa A. Rossow is author of the major front section surveying the erect bush-clovers of Kansas. After pursuing graduate studies at the University of Kansas, she served as an Americorps volunteer in the southwest, teaching elementary children about plants and creating school gardens. Currently she is working at the New York Botanical Gardens as a Curatorial Assistant on the “Catalog of Vascular Plant Species of Central Brazil” project funded by the National Science Foundation. Tom Eddy compiled the prevention and control section and is professor of biology at E.S.U. The updated map of sericea in Kansas is courtesy of J. Vogel of the Kansas Department of Agriculture. The sericia lespedeza calendar was developed by Jeanne Heuser, Technical Information Specialist with the U.S. Geological Survey.


SERICEA LESPEDEZA IN KANSAS
Including Erect Bush-clovers of Kansas

by Melissa A. Rossow

INTRODUCTION

Sericea lespedeza, or Chinese bush-clover (scientific name Lespedeza cuneata (Dum. Cours.) G. Don), is a member of the bean family (Fabaceae). It was introduced to the U.S. from East Asia as a useful species, but has become a serious pest in Kansas, out-competing native species and impacting grassland and woodland communities. There are 18 species of the genus Lespedeza in the U.S., seven introduced and 11 native. Nine species occur in Kansas. Of the seven natives, four share an upright—or erect—growth form with sericea lespedeza and are occasionally mistaken for it. Because the native species can be difficult to distinguish from sericea lespedeza, and because sericea lespedeza sometimes grows in mixed stands with native species, efforts to control sericea lespedeza may impact native bush-clovers. This booklet recounts the history of sericea lespedeza in Kansas, describes some biological attributes that make it such a successful pest, and serves as a guide to help distinguish the four erect, native Lespedeza species from one another and from the invasive sericea lespedeza.

HISTORY

The North Carolina Agricultural Experiment Station first introduced sericea lespedeza to the U.S. in 1896. By 1924, the United States Department of Agriculture (USDA) was cultivating the species at the Arlington Virginia Experiment Farm. Sericea lespedeza was originally thought to be useful for erosion control, hay, and wildlife cover. It was employed as a ground cover on poor soils and, by the 1940s, as a pasture crop. The USDA reported that the leaves make excellent mulch, and the plant’s fibers make decent paper. It is also a good honey plant. However, these benefits are greatly outweighed by its impact on native plants in Kansas.

During the 1930s, sericea lespedeza was introduced to southeast Kansas where it was planted as cover on strip-mined land. It was planted as wildlife habitat around state and federal reservoirs from the 1940s into the 1970s. In the 1950s, it was used in soil bank plantings along with introduced grasses. In recent years, native grass seed contaminated with sericea lespedeza has been implicated in spreading plants to Conservation Reserve Program (CRP) plantings in central and western Kansas.

There are many definitions for the word “weed.” Simply stated, a weed is a plant growing where humans do not want it. When a weed becomes a threat to humans and their activities, especially economic activities, the species may be defined by law as “noxious.” Sericea lespedeza was declared a “county option noxious weed” in Kansas in 1988 and a “state wide noxious weed” on July 1, 2000, making Kansas the only state in the U.S. to list sericea lespedeza as a noxious weed. The Kansas Department of Agriculture (KDA) Plant Protection and Weed Control Program lists 12 species as noxious in Kansas. State law requires landowners to “control the spread of and... eradicate all weeds declared by legislative action to be noxious on all lands owned or supervised by them and to use such methods for that purpose and at such times as are approved and adopted by the department of agriculture.”

BIOLOGY AND LIFE HISTORY

Sericea lespedeza has been so successful in spreading because it is drought tolerant, thrives in nutrient-poor, shallow soils, has few natural predators in North America, reproduces both sexually and asexually, and sets large numbers of seeds.

Sericea lespedeza is drought tolerant and will grow in poor quality (acidic to alkaline), shallow soils. The combination of a taproot and a fibrous root system give plants the ability to survive when soil moisture is limited. This hardiness gives it a competitive advantage over many native species, especially in degraded habitats.

Bush-clovers produce two kinds of flowers: chasmogamous ones, which open for insect-pollination, primarily by bees, and cleistogamous ones, which are greatly reduced in size and morphology, and are self-pollinated. Cleistomamy is induced by a variety of environmental factors, including drought, heat, and day length.
Cleistogamous flowers are generally produced after chasmogamous ones, towards the end of the growing season. Both kinds of flowers are distinguished by their elongated, recurved, and persistent style, which is shorter and straight on chasmogamous fruits (Figure 2).

One stem of sericea lespedeza (called a ramet) may produce up to 1500 seeds. There are about 350,000 seeds in a pound, and one acre of sericea lepedeza may produce 300-600 pounds of seed. A single acre of sericea lespedeza may produce one to two hundred million seeds, of which 10–15% germinate. Germination studies have shown that native bush-clovers may remain viable for more than a half a century, but there are no published studies on seed longevity in sericea lespedeza. It is likely that they are long-lived, however, and this is a problem because, even if the mature plants are eliminated from a site, many viable seeds may remain in the soil.

Rhizomes (underground stems, incorrectly referred to by some researchers as “underground stolons”) of bush-clovers are short and woody, and often grow near the surface of the soil. Buds on rhizomes do not break dormancy until late spring. Asexual reproduction is accomplished through vegetative propagation; new plants are formed by longitudinal fragmentation of the woody rhizome, which follows the development of the taproot on the part of the rhizome that becomes separated from the parent plant.

There are few natural predators of sericea lespedeza in North America, and it is seldom affected by disease and insects here. The leaves are occasionally stripped by grass armyworm, Pseudaletia unipuncta (Haworth), lespedeza webworm, Tetralopha scortealis (Lederer), and American grasshopper, Schistocera Americana (Drury). Mature plants are mostly ungrazed by livestock due to the high levels of tannins. Tannins are phenolic compounds found in plants. They are used by humans to tan hides. Tannins interfere with protein absorption in the gut. Livestock may graze young plants that have not yet accumulated high tannin levels.

ETHNOBOTANY OF BUSH-CLOVERS

The only bush-clover known to have been used in North America is Lespedeza capitata or round-head bush-clover. Daniel Moerman’s reference work Native American Ethnobotany (Timber Press, Portland, Oregon, 1998) cites L. capitata as a poison antidote, a moxa (a substance placed on the skin and ignited to act as a counter-irritant), a neuralgia and rheumatism treatment, a remedy for “bad blood” and sometimes as a tea beverage.

In A Field Guide to Medicinal Plants: Eastern and Central North America (Houghton Mifflin, Boston, 1990), Stephen Foster and James A. Duke report that Lespedeza capitata is used for chronic kidney disease, lowering blood cholesterol, anti-tumor activity, and in reducing nitrogen levels in urine. Hemeocan, Loiron, and Dolisos are Canadian companies that manufacture and market a homeopathic form of Lespedeza capitata. Homeocan lists it as a remedy for treating both renal failure and clogged arteries.

The colloquial name for Lespedeza in Japanese is Hagi zoku, while the specific name for sericea lespedeza is Medogi-hagi or as it is most often abbreviated Medo-hagi. Medogi (pronounced shi) indicates the Chinese character yi, which means divinition, and hagi means bush-clover. In the past, woody stems of the plant (usually 50) were used as divining rods by Chinese divinators.

Key to and Descriptions of the Erect Bush-clovers of Kansas

Introduced or native perennial herbs with woody underground stems (often flowering first year); stems erect or ascending, often branched, smooth or hairy. Leaves alternate, petiolate, compound with three leaflets; leaflets entire, about equal in shape, with pointed tips; stipules persistent, linear or whisker-like to narrowly triangular. Inflorescences in panicles, spikes, or head-like clusters along the upper half of the stem. Flowers pea-like, borne in pairs; calyx bell-shaped, 5-toothed, the teeth somewhat equal, persistent in fruit; petals purple, pinkish, or yellowish to white; upper petal (banner) rounded to oblong, with narrowed base; lower (keel) and side (wings) petals about equal; stamens in two groups; style long, thread-like. Fruits 1-seeded pods; seeds dark-colored, smooth.

Introduced or native perennial herbs with woody underground stems (often flowering first year); stems erect or ascending, often branched, smooth or hairy. Leaves alternate, petiolate, compound with three leaflets; leaflets entire, about equal in shape, with pointed tips; stipules persistent, linear or whisker-like to narrowly triangular. Inflorescences in panicles, spikes, or head-like clusters along the upper half of the stem. Flowers pea-like, borne in pairs; calyx bell-shaped, 5-toothed, the teeth somewhat equal, persistent in fruit; petals purple, pinkish, or yellowish to white; upper petal (banner) rounded to oblong, with narrowed base; lower (keel) and side (wings) petals about equal; stamens in two groups; style long, thread-like. Fruits 1-seeded pods; seeds dark-colored, smooth.

[Botanical terms used here are labeled on Figures 2 & 3]

1a. Leaflets widest near the tip, mostly wedge-shaped ......................................................................... Lespedeza cuneata

1b. Leaflets widest near the middle, linear, oblong, oval or oval to circular ....................... go to lead 2

 

2a. Calyx teeth nearly equal to, or longer than, flowers and fruits; flowers white to yellowish with a purple base ....................... go to lead 3

 

 

3a. Leaflets 1 1/4–1 3/4 times longer than wide, oval to circular; inflorescences long-stalked, with few too many head-like to elongate clusters arising above the leaves; extreme SE Kansas (Cherokee Co.) ....................... Lespedeza hirta

3b. Leaflets 2 ½–5 times longer than wide, oval, oblong, or somewhat diamond shaped; inflorescences stalked, cylindrical, round-topped clusters, arising above the leaves; E 2/3 of Kansas ....................... Lespedeza capitata

 

2b. Calyx teeth nearly equal to, or longer than, flowers and fruits; flowers white to yellowish with a purple base ....................... go to lead 4

 

 

4a. Leaflets 1 ½ –3 times longer than wide, oblong to oblong-oval, rarely oval or circular, upper surface more or less hairy, lower surface densely hairy; stems unbranched above; S ½ of Kansas, especially in sandy prairies and woodlands ....................... Lespedeza stuevei

4b. Leaflets 3–7 times longer than wide, linear to narrowly oblong, smooth to hairy on both sides; stems branched above; E ½ of Kansas, sporadic in the west ............. Lespedeza virginica

 

KSN - Vol. 56, No. 1 - Figure 2
Figure 2.
Chasmogamous Lespedeza flower. a. calyx teeth; b. banner petal; c. wing petal; d. keel petals.

KSN - Vol. 56, No. 1 - Figure 3
Figure 3.
Fruit from a cleistogamous Lespedeza flower. a. calyx teeth; b. cleistogamous style; c. fruit.

Lespedeza capitata Michx; round-head bush-clover. (Figures 6 and 9)
Stems erect or ascending, 1 ½–6 ft tall, simple or branched above, very hairy. Leaves shortstalked; leaflets widest near the middle, oval, oblong, or somewhat diamond shaped, 1–2 in long, 1/8–3/4 in wide, 1 ½–5 times longer than wide, upper surface smooth to sparsely hairy, lower surface densely silky; stipules long, slender, narrowly tapering towards the tip, 1/8–1/4 in long. Inflorescences stalked, cylindrical, round-topped clusters, arising above the leaves. Flowers 1/2–3/4 in long; calyx teeth ½–3/4 in long, petals white or yellowish with a purplish base; banner longer than keel and equal to or longer than the wings. Fruits to 1/8 in long; seeds less than 1/8 in long, olive, brown, or black. Upland tallgrass, mixed-grass, and sand prairies. Frequently planted in CRP and reseeded prairies. Occurring in the eastern two-thirds of the state.

KSN - Vol. 56, No. 1 - Figure 4
Figure 4.
Lespedeza cuneata

KSN - Vol. 56, No. 1 - Figure 5
Figure 5.
Lespedeza virginica

 

KSN - Vol. 56, No. 1 - Figure 6
Figure 6.
Lespedeza capitata

KSN - Vol. 56, No. 1 - Figure 7
Figure 7.
Lespedeza hirta

KSN - Vol. 56, No. 1 - Figure 8
Figure 8.
Lespedeza stuevei

Lespedeza cuneata (Dum. Cours.) G. Don; sericea lespedeza, Chinese bush-clover. (Figures 4 and 10)
Stems erect with spreading or ascending branches, 1 ½–6 ft tall, hairy. Leaves crowded; stipules whisker-like to ½ in long; leaves stalkless or with a very short stalk; leaflets mostly wedge-shaped, ½–1 in long, with flattened hairs, gray-green, tips blunt or sometimes with a tiny point. Inflorescences few flowered clusters, arising above the leaves. Flowers 1/4–1/2 in long; white or yellowish, banner often with a purplish spot; calyx teeth 1/8–1/4 in long. Fruits to 1/8 in long; hairless or short hairy at maturity; seeds less than 1/8 in long, olive to brown, often splotchy. Disturbed sites, including old fields, roadsides, pastures, and occasionally introduced in CRP. Invading woodlands, tallgrass prairies, and other native plant communities. Occurring in the eastern half of the state, and to be expected westward.

Lespedeza hirta (L.) Hornem.; hairy bush-clover. (Figures 7 and 11)
Stems erect or ascending, 1 ½–6 ft tall, branched above, densely hairy. Leaves long-stalked; leaflets widest near the middle, oval to circular, ½–1 ½ in long, 1/4–1 1/4 in wide, 1 1/4–1 3/4 times longer than wide, upper surface smooth to hairy, lower surface hairy; stipules threadlike. Inflorescences long-stalked, with few to many head-like to elongate flower clusters arising above the leaves. Flowers 1/4–1/2 in long; white or yellowish with a purplish base; calyx teeth 1/8–1/4 in long. Fruits oval to elliptic, 1/8–1/4 in long; hairy; seeds to 1/8 in long, brown or purplish-black, shiny. Open woods and stream valleys. Occurring in the Ozarks, confined to Cherokee County.

Lespedeza stuevei Nutt.; tall bush-clover. (Figures 8 and 11)
Stems erect or ascending, 1 ½–4 ½ ft tall, unbranched above, densely hairy. Leaves longstalked; leaflets widest near the middle, oblong to oblong-oval, rarely oval to circular, 1/4–1 ½ in long, 1/4–3/4 in wide, 1 ½–3 times longer than wide, upper surface more or less hairy, lower surface densely hairy; stipules linear to whisker-like, 1/8–1/4 in long. Inflorescences dense racemes along the upper part of the stem. Flowers 1/8–1/4 in long, purple; calyx teeth less than 1/8 in long; banner and wings about equal, both longer than keel. Fruits oval to elliptic, 1/4–1/2 in long, usually hairy; seeds to 1/8 in long, olive to dark brown, shiny. Open woodlands, sand tallgrass prairies, and sand prairies. Occurring in the southern half of the state.

Lespedeza virginica (L.) Britton; slender bush-clover. (Figures 5 and 12)
Stems erect or ascending, 1–3 ft tall, usually branched above, hairy. Leaves long-stalked; leaflets widest near the middle, linear to narrowly oblong, 1/4–1 ½ in long, 1/8–1/2 in wide, 3–7 times longer than wide, smooth to hairy on both sides; stipules thread-like, 1/8–1/4 in long. Inflorescences racemes on stalks shorter than to slightly longer than the leaves, crowded toward the end of the stems. Flowers 1/2–1/2 in long, purple; calyx teeth less than 1/8 in long; keel usually a little longer than banner and wings. Fruits oval to elliptic, 1/4–1/2 in long, usually hairy; seeds to 1/8 in long, olive to brown. Open woodlands, sandy stream valleys, thickets, and tallgrass prairies. Rarely introduced in CRP. Primarily in the eastern half of the state, sporadic in the west.

DISTRIBUTION OF ERECT BUSH-CLOVERS IN KANSAS

Distributions of erect bush-clovers in Kansas are presented in Figures 4–7. Distributions for all species except L. cuneata are based exclusively on herbarium specimens housed at Emporia State University, Fort Hays State University, Kansas State University, Pittsburg State University and the University of Kansas. Distributions for L. cuneata are based on a combination of herbarium specimens and sightings reported to KDA State Weed Specialist Bill Scott.

KSN - Vol. 56, No. 1 - Figure 9 Figure 9. Distribution of Lespedeza capitata in Kansas. (Closed circles represent precise locations; triangles represent records for which only county of collection is known.)
KSN - Vol. 56, No. 1 - Figure 10 Figure 10. Distribution of Lespedeza cuneata in Kansas. (Closed circles represent precise locations; triangles represent records for which only county of collection is known; open circles represent sightings reported to KDA State Weeds Specialist Bill Scott.)
KSN - Vol. 56, No. 1 - Figure 11 Figure 11. Distribution of Lespedeza stuevei and Lespedeza hirta (star, Cherokee Co.) in Kansas. (Closed circles represent precise locations for L. stuevei; triangle represents a record for which only county of collection is known.)
KSN - Vol. 56, No. 1 - Figure 12 Figure 12. Distribution of Lespedeza virginica in Kansas. (Closed circles represent precise locations; triangles represent records for which only county of collection is known.)

HOW YOU CAN HELP

Help track the spread of sericea lespedeza in Kansas. Send plant specimens to the R.L.McGregor Herbarium. Directions for collecting, preparing, and submitting plant specimens are posted on the Herbarium website: http://nhm.ku.edu/herbarium/herbinfo.html. For more information, call (785) 864-4493.

FURTHER READING:

Clewell, Andre F. 1966. Native North American species of Lespedeza (Leguminosae). Rhodora 68: 359–405.

Clewell, Andre F. 1966. Natural History, cytology, and isolating mechanisms of the Native American lespedezas. Bulletin of Tall Timbers Research Station 6. Tall Timbers Research Station, Tallahassee, Florida.

Davidson, J., Walter H. Fick, Gary Kilgore, and Paul D. Ohlenbusch. 1999. Sericea lespedeza: History, characteristics, and identification. Kansas State University, Manhattan, Kansas.

Kansas State Research and Extension. 2000. Sericea Lespedeza and the future of invasive species: A Symposium with a Look to the future. Kansas State University, Manhattan, Kansas.

Sericea Lespedeza: Facts for Biology Teachers, a Summary of the Sericea Lespedeza Symposium held at Emporia State University March 14, 1998. 1998. Kansas Biology Teacher 7(2): 72–77.


PREVENTION AND CONTROL

by Tom Eddy

PREVENTION AND CONTROL

Sericea lespedeza is a serious problem for Kansas farmers and ranchers. The control of sericea lespedeza will require a long term effort because cattle will not graze the mature plant and traditional eradication methods have not been effective. The KDA defines control of this invasive plant as “preventing production of viable seed.” Early spring burning and mowing both increase seed germination. However, late mowing or burning (mid-July through late summer) reduces the vigor of stands.

Burning
Traditional spring burning in April alone is not effective. It stimulates the germination of seeds by breaking the seed coat so that more new plants can grow. Fall burning reduces the vigor of the sericea lespedeza plants but will also reduce the production of grass the following spring and summer.

Mowing
Mowing, after burning, is somewhat effective if it is followed by an herbicide treatment. The timing of this treatment is the key to success. Burning should occur in early May, mowing a month later, and the herbicide should be applied in October for best results.

Chemical control
Seeds from the plant remain viable in the soil for many years and they can be spread by water, wildlife, and human activities. Chemical control is most effective when sericea lespedeza first invades a pasture. Spot spraying individual plants is cost effective. It is also less damaging to the environment than aerial spraying because there is less spray drift and runoff into water ways. Broadcast applications on the ground are less expensive as well. Aerial spraying may be the only way to reach the plants when the terrain is too hilly or rocky for vehicles. However, herbicides injure other broadleaf prairie plants. A native tallgrass meadow can have over 200 species of wildflowers.
Three chemicals recommended by Kansas State University are Remedy, PastureGard, and Escort XP. Remedy and PastureGard applications work best when new growth is 12 to 15 inches tall, which usually occurs in June. The broadcast rate for Remedy is 1.5 pints per acre. The rate for PastureGard is 2.0 pints per acre. Escort XP is most effective when applied to the plants in the fall when both types of flowers are produced. If fall weather is dry, application should be delayed until these flowers are present. Spray should not be applied in dry weather because poor herbicide uptake and poor control can result. Escort XP should be applied at the broadcast rate of 0.5 ounces per acre. A surfactant, a surface wetting agent, is needed to help the chemical adhere to the leaves.

Biological Control
A natural control of sericea lespedeza is the lespedeza webworm. This moth’s larvae will wrap a stem in a silken web and then consumes the leaves. Without leaves the plant cannot make enough energy to produce seeds. Webworms are not as dependable as other methods of control because they do not tolerate extended periods of drought and high temperatures.



Grazing Control

Grazing young sericea lespedeza plants in the early spring when the plants have lower tannin content has shown some promise for control. Cattle, confined in small pasture units, can be used to intensively graze the plant’s new growth. Another promising method for control is patch burning. This technique concentrates cattle on small burned areas within a larger pasture. The cattle are drawn to the burn sites where they feed on the newly emerged plants. Scientists have also found that the chemical polyethylene glycol, when applied to the foliage of sericea lespedeza makes it more digestible for cattle. Polyethylene glycol keeps tannins from interfering with the animal’s absorption of protein. It also may make it more likely that the plant will be eaten because the plant will be less bitter without the tannins. Currently the cost of this treatment prohibits its widespread use.

Goats are another management option. Goats tolerate the higher tannin content in sericea lespedeza plants; in fact they seem to like the tannins. They also will consume the plants in all stages of growth. In addition to reducing the number of sericea lespedeza plants, grazing goats lower seed production, and eat other introduced plants.

 

 

2005 Reported Sericea Lespedeza Acres

On 3/31/10, the image presented here in the original edition of this issue was removed per the author due to the dated material presented.


The Kansas School Naturalist Department of Biology 
  College of Liberal Arts & Sciences 
Send questions / comments to
Kansas School Naturalist.
 Emporia State University