Japan, Korea, China, Malaysia and India
Japanese stiltgrass, or Nepalese browntop, is an annual grass with a sprawling habit. It germinates in spring and grows slowly through the summer months, ultimately reaching heights of 2 to 3½ ft. The leaves are pale green, lance-shaped, asymmetrical, 1 to 3 in. long, and have a distinctive shiny midrib. Slender stalks of tiny flowers are produced in late summer (August through September-early October) and dry fruits called achenes are produced soon afterwards.
Japanese stiltgrass is especially well adapted to low light conditions. It threatens native plants and natural habitats in open to shady, and moist to dry locations. Stiltgrass spreads to form extensive patches, displacing native species that are not able to compete with it. Where white-tail deer are over-abundant, they may facilitate its invasion by feeding on native plant species and avoiding stiltgrass. Japanese stiltgrass may impact other plants by changing soil chemistry and shading other plants. The interaction between stiltgrass and the Northern Pearly Eye (
), a member of the brush-footed butterfly family Nymphalidae, is unclear. This butterfly is rare to uncommon along the Potomac River in the Washington, DC area. Its caterpillar eats grasses. Dr. Robert Robbins, a Smithsonian entomologist and butterfly specialist takes weekly walks at Great Falls, Maryland, and made the following observations. The Northern Pearly Eye occurs uncommonly at Great Falls from May to October (maybe 2-15 individuals seen over the entire flight period). Adults were especially common during the summer of 2004. The butterfly became exceedingly common during the summer of 2005 when about 20 adults were seen during a 2 hour walk, especially in the vicinity of stiltgrass, on which a female was observed placing an egg. In May 2006, the butterfly was again common, but the population then crashed, and only 2-3 individuals were seen from June to October 2006. Further investigation is needed to study the potential impacts of stiltgrass on this and possibly other butterflies or other insects that utilize stiltgrass as an alternative host plant.
DISTRIBUTION IN THE UNITED STATES
According to the WeedUS Database, Japanese stiltgrass has been reported to be invasive in natural areas in 15 eastern states inculding Connecticut, Delaware, Georgia, Indiana, Kentucky, Maryland, Massachusetts, New Jersey, New York, North Carolina, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington, DC.
HABITAT IN THE UNITED STATES
Stiltgrass occurs in a wide variety of habitats including moist ground of open woods, floodplain forests, wetlands, uplands, fields, thickets, paths, clearings, roadsides, ditches, utility corridors, and gardens. It readily invades areas subject to regular mowing, tilling, foot traffic, and other soil disturbing activities as well as natural disturbances such as the scouring associated with flooding. Stiltgrass appears to prefer moist, acidic to neutral soils that are high in nitrogen.
First documented in Tennessee around 1919, stiltgrass may have accidentally escaped as a result of its use as a packing material for porcelain.
BIOLOGY & SPREAD
Japanese stiltgrass is an annual grass, with all plants dying each fall. It is a colonial species that spreads during the summer and fall by rooting at stem nodes that touch the ground. Individual plants may produce 100 to 1,000 seeds that fall close to the parent plant from both self-fertilizing and cross-fertilizing flowers. Seed may be carried further by water currents during heavy rains or moved in contaminated hay, soil, or potted plants, and on footwear and vehicles. Stiltgrass seed remains viable in the soil for five or more years and germinates readily. Deer and other grazers reportedly do not browse it, though they have been found to spread the seeds. Stiltgrass leaves a thick layer of thatch after dieback each year in heavily invaded areas, and while leaves decompose quickly, stems do not. Like other invasive species, stiltgrass is physiologically adaptive. For example, it is able to withstand low light levels where nutrient levels are sufficient, and able to withstand low nutrient levels where light levels are sufficient. While stiltgrass can photosynthesize in low light conditions and respond quickly to the changing light conditions typically found on the forest floor, the very low light conditions found beneath a multilayered forest canopy will limit its growth.
A variety of control methods are available for stiltgrass, depending on the extent of the infestation, the type of habitat, and the availability of labor and other resources. Preventing the introduction of stiltgrass from infested to non-infested areas should be a priority. Early control of new infestations will also reduce the likelihood of establishment and expansion. Manual removal of plants results in unavoidable disturbance to the soil which can result in additional germination of stiltgrass seed. Using an herbicide leaves the plants and soil in place, thus minimizing that likelihood.
No biological controls are currently available for this plant.
For extensive stiltgrass infestations, use of a systemic herbicide such as glyphosate (e.g., Roundup Pro®) is a practical and effective method if used with some caution. Glyphosate is a non-specific herbicide that will kill or damage almost any herbaceous plant and possibly some woody plants it contacts. Roundup Pro® is surfactant-loaded (no additional surfactant needed) and the surfactant is not lethal to amphibians and aquatic invertebrates like the polyoxyethyleneamine surfactant in Roundup Classic® is. Roundup Pro® carries the 'Caution' signal word while Roundup Classic® carries 'Warning'. When treating stiltgrass in wetland sites, use Rodeo® or other formulation labeled for wetlands. Apply a 2% solution of Roundup® or Rodeo® mixed with water (8 oz. per 3 gals. mix) and a surfactant in late summer. Be careful to avoid application to non-target plants.
Some researchers have also found success using the pre-emergent herbicide imazapic which is the active ingredient found in Plateau® (for government use only), and Journey® (for all other applicators). Imazapic is most effective against stiltgrass when applied in March in the Mid-Atlantic states. The best rate for maximum selectivity is 4 oz. per acre, applied as a broadcast application with backpack sprayers. Sprayers should be fitted with an 8003E flat fan nozzle and calibrated at 15 to 20 gpa. Plateau® and Journey® can be applied continually through germination of the stiltgrass and throughout the summer during its peak growth. No surfactant is necessary for pre-emergent applications. As germination nears, begin to add 1/4% non-ionic surfactant to the mixture.
Another option that may be appropriate for certain situations is to apply a pre-emergent (only) treatment with Pendulum® Aquacap™ (active ingredient is pendimethalin) at 2.4 qts. to 4.8 qts. per acre (15 to 20 gpa). The higher rates have provided season long control.
Note: Calibration of spray equipment will ensure that the correct rate of herbicide mix is actually applied to the plants. Actual rate of application can vary widely based on different skills and techniques of applicators. These differences can lead to under-application or over-application of herbicide mix which can affect the efficacy of the treatment. For this reason, it is important to calibrate spray equipment before conducting herbicide applications.
Stiltgrass is a shallow-rooted annual that can be pulled by hand throughout the growing season, especially when the soil is moist and entire plants with roots can be removed. Pulling is easier and probably more effective in mid-to-late summer when the plants are much taller and more branched. At this stage, entire plants can be easily removed by grabbing the basal portion of a plant and pulling firmly. In short time, a fair amount of stiltgrass can be pulled and piled up to dehydrate on site. If plants are already in the fruiting stage, they should be bagged and disposed of offsite to prevent dispersal of seed. Also, try to avoid pulling native grasses like Virginia cutgrass (Leersia virginia) that often grow intermingled with stiltgrass and may be difficult to distinguish from it. Because hand pulling plants disturbs the soil and may expose stiltgrass seed from previous seasons, late season pulling will avoid the likelihood of seed germination. Hand pulling of plants will need to repeated and continued for many seasons until the seed bank is exhausted.
Stiltgrass can be mowed in late summer (i.e., August through September) when the plants are flowering but preferably before seed is produced. This can be done using a lawn mower or "Weed Whacker" type machine or a scythe. Because stiltgrass is primarily an annual plant, cutting late in the season before the plants would die back naturally avoids the possibility of regrowth. Recent information suggests that stiltgrass plants that are cut early in the summer respond by regrowing and flowering soon after cutting, much earlier than they would normally flower. This is another reason to consider cutting in late summer to fall rather than during the early summer months.
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS.
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
For more information on the management of Japanese stiltgrass, please contact:
Art Gover, PENNDOT Roadside Vegetation Management Project, Department of Horticulture, The Pennsylvania State University, University Park, PA; (814) 863-1184 phone/fax; aeg2(at)psu.edu
Fred Yelverton, North Carolina State University, Raleigh, NC; (919) 515-5639; Fred_Yelverton(at)ncsu.edu
Joseph C. Neal, North Carolina State University, Raleigh, NC; joe_neal(at)ncsu.edu
Jeffrey F. Derr, Virginia Polytechnic Institute and State University, Virginia Beach, VA; jderr(at)vt.edu
Jil M. Swearingen, National Park Service, Center for Urban Ecology, Washington, DC
Sheherezade Adams, University of Maryland, Frostburg, MD
Jim Bean, BASF Corporation, Collierville, TN
Art Gover, The Pennsylvania State University, Philadelphia PA
Todd L. Mervosh, Weed Scientist, The Connecticut Agricultural Experiment Station, Windsor, CT Robert K. Robbins, Smithsonian Institution, Washington DC
Chuck Bargeron, www.invasive.org, University of Georgia, GA
Barden, Lawrence. 1987. Invasion of
(Poaceae), an exotic, annual, shade-tolerant, C-4 grass, into a North Carolina floodplain. The American Midland Naturalist 118 (1):40-45.
Barden, Lawrence. 1991. Element Stewardship Abstract:
. The Nature Conservancy.
Claridge, K and Franklin, SB. 2003. Compensation and plasticity in an invasive plant species. Biological Invasions 4: 339-347.
Cole, PG and Weltzin, JF. 2004. Environmental correlates of the distribution and abundance of
, in east Tennessee. Southeastern Naturalist 3: 545-562.
Cole, PG and Weltzin, JF. 2005. Light limitation creates patchy distribution of an invasive grass in eastern deciduous forests. Biological Invasions 7: 477-488.
Ehrenfeld, JG, Kourtev, P and Huang, W. 2001. Changes in soil functions following invasions of exotic understory plants in deciduous forests. Ecological applications 11: 1287-1300.
Fairbrothers, D. E. and J.R. Gray. 1972.
(Gramineae) in the United States. Bulletin of the Torrey Botanical Club 99:97-100.
Horton, JL and Neufeld, HS. 1998. Photosynthetic responses of
(Trin.) A. Camus, a shade-tolerant, C4 grass, to variable light environments. Oecologia 114: 11-19.
Hunt, D. M. and Robert E. Zaremba. 1992. The northeastward spread of
(Poaceae) into New York and adjacent states. Rhodora 94:167- 170.
LaFleur, A. 1996. Invasive plant information sheet: Japanese stiltgrass. The Nature Conservancy, Connecticut Chapter Connecticut, Hartford, CT.
Mehrhoff, LJ. 2000. Perennial
(Poaceae): an apparent misidentification? Journal of the Torrey Botanical Society 127: 251-254.
Miller, J.H. 2003. Nonnative invasive plants of southern forests: a field guide for identification and control. Gen. Tech. Rep. SRS-62. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 93 pp.
Redman, Donnell E. 1995. Distribution and habitat types for Nepal microstegium [
(Trin.) Camus] in Maryland and the District of Columbia. Castanea 60(3): 270-275.
Rhoads, A.F. and T.A Block. 2000.The Plants of Pennsylvania, An Illustrated Manual. University of Pennsylvania Press. 1061 pp.
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Japanese Stiltgrass (
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Southeast Exotic Pest Plant Council Invasive Plant Manual
Japanese Grass or Eulalia
(Trin.) A. Camus.
Microstegium is an annual colonial grass that spreads rapidly into disturbed lowland areas. Inconspicuous at first, populations may go unnoticed until they have displaced native communities. It is a C-4 shade tolerant plant that can survive and reproduce under a closed forest canopy.
Microstegium is a decumbent and branched annual grass reaching a height of 60-100 cm (24-39 in).
Culms are 1.5 m (59 in) long with glabrous nodes and internodes.
Cauline leaves are alternate, lanceolate, 10 cm (4 in) long, 2-15 mm (0.08-0.6 in) wide, and sparsely pubescent on both surfaces with ciliate margins.
Racemes are terminal and may be solitary or in a set of two or three. Spikelets are in pairs, one sessile and one pedicellate, and 4.5-5mm (0.17-0.2 in) long. Blooms August-September.
Grain is yellow to red, ellipsoid, 2.8-3.0 mm (0.1-0.12 in) long. Seeds mature over a period of about two weeks in September-October.
Microstegium is an annual C-4 shade tolerant grass in the Poaceae family. It is colonial in nature, rooting from the nodes, and may form dense monotypic stands. Reproduction is exclusively from seed. Each plant may produce from 100-1,000 seeds that remain viable in the soil for five or more years. Seed dispersal is primarily by animals, flooding, and deposition with fill dirt. This plant spreads rapidly into disturbed areas but can invade undisturbed areas by forming satellite populations brought in by animals or flooding. On fertile mesic sites Japanese grass can replace competing ground vegetation within 3-5 years.
Microstegium is adapted to low light conditions. At 18% of full sunlight dry matter production is not significantly reduced from production in full sunlight. It will grow and produce seed in light levels as low as 5% of full sunlight.
Origin and Distribution
Microstegium is native to Japan, Korea, China, Malaysia, and India. It was first identified in the U.S. at Knoxville, Tennessee in 1919, and in 1933 was collected in western North Carolina. By 1964, the grass had spread to 35 counties in North Carolina. By 1972, it had been identified in 14 eastern states, and in 1978, it was collected in Arkansas. Microstegium can be found throughout the state of Tennessee, primarily in previously disturbed mesic areas.
Microstegium may be confused with cutgrass (
Willd.) or knotweed (
L.). Cutgrass has distinctly longer leaves (1.5 dm [6.0 in]) and shorter spikelets (2.5-3 cm [1.0-1.2 in]) than microstegium. Knotweed is distinguished from microstegium by pale to dark pink calyx and glossy black nutlets.
Photo by Ted Bodner
Photo by Ted Bodner
Photo by James H. Miller
Alluvial soil found in flood plains and stream sides is ideal habitat for microstegium. Other typical habitats include damp fields, lawns, mesic woodland edges, roadsides, and ditches. It is commonly found in areas of natural (e.g., flood scouring) or artificial (e.g., mowing, tilling) disturbance, but can invade undisturbed areas. Microstegium has been observed growing at an elevation of 1,200 m (3,840 ft), but typically is not found on upland sites. Deer avoid microstegium, which allows it a competitive advantage in over browsed areas.
Mow plants as close to the ground as possible using a weedeater or similar grass cutting tool. Treatments should be made when plants are in flower and before seeds are produced. Treatments made earlier may result in plants producing new seed heads in the axils of lower leaves.
Herbicide treatments should be made late in the growing season but, before the plants set seed. Treatments made earlier in the growing season may allow a second cohort of plants to produce seeds.
Glyphosate: Apply a 2% solution of glyphosate and water plus a 0.5% non-ionic surfactant to thoroughly wet all foliage. Do not spray to the point of runoff. Ambient air temperature should be above 65Â°F to ensure translocation of the herbicide to the roots. Do not apply if rainfall is expected within two hours following application.
Sethoxydin: Apply a 1.5% solution of sethoxydin and water plus a 1% nonphytotoxic vegetable-based oil to all foliage on a spray-to-wet basis. Do not spray to the point of runoff. Ambient air temperature should be above 65Â°F. Do not apply if rainfall is expected within one hour following application.
Barden, L. S. Invasion of
(Poaceae), an exotic, annual, shade-tolerant, C-4 grass, into a North Carolina floodplain. American Midlands Nature Journal 118(1):40-45; 1987.
Fairbrothers, H. L; Gray, J. R.
(Trin) A. Camus (Graminaceae) in the United States. Bulletin of the Torrey Botanical Club 99:97-100; 1972.
Gleason, H. A.; Cronquist, A. Manual of vascular plants of northeastern United States and adjacent Canada. 2nd ed. The New York Botanical Garden; 1991.
Goel, A. K.; Uniyal, B. P. On the occurrence of a few grasses in Pakistan and Nepal (
). Journal of Economic and Taxonomic. Botany: 4(3): 43; 1983
Hunt, D. M.; Zaremba, R. E. The northeastward spread of
(Poaceae) into New York and adjacent states. Rhodora 94(878):167-170; 1992.
Radford, A. E.; Ahles, H. E.; Bell, C. R. Manual of vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press; 1968.
Redman, D. Distribution and habitat types for Nepal microstegium (
[Trin.]Camus) in Maryland and the District of Columbia. Castanea 60(3):270- 275; 1995.
Winter, K.; Schmitt, M. R.; Edwards, G.E.
, a shade adapted C-4 (carbon pathway) grass (comparison of growth with
). Plant Science Letter 24(3):311-318; 1982.
Woods, F. Southeast Region Resource Activity Report GSMNP. USDI National Park Service Agreement # CA-5460-5-8004. Research on Japanese Grass and Princess Trees; 1987.
Japanese stiltgrass, Japanese stilt grass, Japanese grass, Mary's grass, Nepalgrass, basketgrass, microstegium, Nepalese browntop, Chinese packing grass
is a delicate, sprawling, annual grass that is 0.5-3.5 ft. (0.2-1.1 m) in height. The stems can root at the nodes.
The leaves are pale-green, alternate, lance-shaped, 1-3 in. (2.5-7.6 cm) long, asymmetrical with a shiny, off-center midrib. Upper and lower leaf surface is slightly pubescent. A silvery line runs down the center of the blade. Stems usually droop.
Flowering begins in September, when delicate flower stalks develop in the axils of the leaves or at the top of the stems.
Fruit is produced from late September through early October.
Most commonly a invader of forested floodplains,
is also found in ditches, forest edges, fields, and trails. It is very shade tolerant and can completely displace native vegetation. It is native to Asia and was accidentally introduced into North America sometime around 1920. It has previously been used as packing material for porcelain, possibly explaining its accidental introduction.
is a shade tolerant, annual C4 grass (family Poaceae). It is a straggling or decumbent plant, usually 6-10 dm in height, and the reclining stems can grow up to 1.0 m (40 in) long. Its culms (stems) are typically branched, rooting at the lower nodes, and the nodes and internodes are smooth and hairless. The lanceolate leaf blades are 5-8 cm long and 2-15 mm wide, sparsely pubescent on both surfaces, and distinctly tapered at both ends. The ligules are membranous, usually ciliate, and are 0.5-2.0 mm long.
The terminal or axillary inflorescence is a raceme, 2-7 cm long, with an elongate peduncle and an angled disarticulating rachis. The hirsute fertile spikelets are deciduous, and occur in pairs, with one spikelet sessile and the other pedicellate. The glumes are equal in length (4.5-5.0 mm) and awnless. The first glume is flat and 2-3 veined. The second glume is keeled and 3-veined. There are two lemmas per spikelet, with the lower one sterile and the upper, fertile one awnless or often with a slender awn 4-8 mm. Both cleistogamous (flowers closed at pollination) and chasmogamous (flowers open) conditions have been reported for
in Japan, with the axillary flowers all being cleistogamous (Tanaka 1975, in Barden 1987).
The fruit or caryopsis (grain) of
is yellowish to reddish, and ellipsoid (2.8-3.0 mm) in shape. Fruiting occurs in September and October in North America.
can be distinguished from other grasses by its thin, pale green, tapered leaf blades, and by its multiple spikelets that may be either terminal or arising from leaf axils. The alternate leaves have a silvery stripe of reflective hairs down the middle of the upper leaf surface. In the fall, identification becomes somewhat easier after the plant develops a slight purplish tinge.
is an annual, there has been some confusion regarding whether
also occurs as a rhizomatous, perennial (Mehrhoff 2000).
According to Mehrhoff (2000), this confusion resulted when specimens of a native perennial,
, were incorrectly identified as
. The annual
can be distinguished from
(which it frequently grows alongside) by the former’s ciliate leaf sheath
collars and paired spikelets (versus
glabrous or pubescent leaf sheaths and 1-flowered spikelets).
is an annual C
grass native to Asia from India and Japan. It possesses characteristics typical of many invasive species: it grows quickly, fruits within a single season, produces abundant seed, and easily invades habitats that have been disturbed by natural (e.g., flood scouring) and anthropogenic (e.g., mowing, tilling) sources.
was first discovered in the United States in 1919
, and has since spread rapidly to
all states east of the Mississippi, and south of and including Connecticut.
is locally abundant, able to displace native wetland and forest understory vegetation with its dense, expanding monospecific patches. It is usually found under moderate to dense shade in moist conditions, but it does not persist in areas with periodic standing water, nor in full sunlight.
Once established, the removal of
requires major eradication and restoration efforts (Bruce et al. 1995).
Manual or mechanical techniques may be the best method for controlling
, since it is a shallowly-rooted annual. Hand pulling, however, is extremely labor-intensive, is feasible only for small infestations, and will need to be repeated and continued at least seven years to exhaust the seed supply in the seed bank.
Mowing or burning early in the season does not control the plant as the plants resprout and new seeds germinate. Following these treatments, plants can still set seed by the end of the season. Mowing may be an effective control method if carried out in late summer, when the plants are in peak bloom but before seed is produced (J. Ehrenfeld, pers. comm.). For extensive infestations, where mechanical methods are not practical, systemic herbicides such as imazameth (tradename Plateau
) or glyphosate (tradename Roundup
, or Rodeo
in wetland sites), or grassspecific herbicides like sethoxydim (tradenames Vantage
) may be effective.
No biological controls are currently available for this plant.
is capable of invading wildland areas and swiftly replacing natural communities with nearly monospecific stands. It is generally slow to invade undisturbed areas, but rapidly fills disturbed areas such as flood-scoured stream sides and sewer line rights-of-way that are mowed once a year. An individual plants of
can produce up to 1000 seeds, and the seeds remain viable in the soil for three to five years. Once established,
is able to crowd out native herbaceous vegetation in wetlands and forests within three to five years (Hunt 1992).
is a C
plant, and C
plants are typically adapted to high temperatures and high light regimes. However, unlike most C
is adapted to low light levels and is able to grow and produce seed in only 5% full sunlight.
may be responsible for altering natural soil conditions, creating an inhospitable environment for many native species. Kourtev et al. (1998)
reported that in areas that have been invaded by
, both litter and organic soil horizons were thinner than in uninvaded areas, and that the pH of soils in invaded sites was significantly higher than in uninvaded sites. There is no indication that
produces allelopathic chemicals.
Established populations of
usurp quality nesting habitat from quail and other wildlife. In addition, it creates excellent habitat for rats, especially cotton rats (Sigmodon spp.), that often prey on the nests of native bobwhite quail and attract other predators as well.
was introduced to North America from Asia, where it is native to India, Nepal, China, and Japan. It was first identified in the United States in 1919 in Tennessee, and by 1960 had spread (probably by hay and soil) to Ohio and Pennsylvania, and all Atlantic coastal states from Florida to New Jersey. It was widely used as a packing material for porcelain from China, and this was likely the means of its introduction into the U.S.
occupies riparian habitats, lawns, woodland thickets, damp fields, and roadside ditches. Reported occurrences of
in North America currently include: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Mississippi, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, and Puerto Rico.
In North America,
occurs in a variety of disturbed sites. It thrives in along mesic roadsides, ditches, woodland borders, floodplains, and streamsides.
It can also be found in mesic upland sites, and is almost always found in moderate to dense shade.
It does not survive, however, in areas with periodic standing water, nor in areas with full sunlight.
Biology and ecology
possesses characteristics typical of many invasive species: it grows quickly, fruits within a single season, produces abundant seed, and easily invades naturally (e.g., flood scouring) and artificially (e.g., mowing, tilling) disturbed habitats. Once established, the removal of
requires major eradication and restoration efforts (Bruce et al. 1995).
is unusual in that although it is a C4 plant, it is adapted to low light conditions.
It can grow and produce seeds at as little as 5% full sunlight, but maximum growth and seed production occurs at 25-50% full sunlight.
Most sites invaded by
in the United States, have acidic soils (pH 5.8 to 4.8), but some populations are on soils derived from limestone or marble with surficial soil that is neutral or only slightly acidic in reaction. Soils on which
occurs are typically average in levels of potassium and phosphorus, and high in nitrogen.
The overall acidity of the soils, however, may limit nutrient availability. Soils are usually moist, and are often well-drained silty loams, sandy loams, or loams. Clay was not a significant component of the upper soil horizons in any of the soils invaded by
at sites studied by Hunt & Zaremba (1992)
No information was found regarding the optimal growing temperatures or the temperature limits of this species. The coldest winter temperature at which invasive populations of M. vimineum occur is approximately -21° to -23° C.
fruits and seeds disperse by water, animals, and by humans. (It was originally introduced as packing material or for basket-weaving.) The floating fruits of
can disperse throughout an entire wetland or alluvial floodplain during high-water events (Mehrhoff 2000).
does not exhibit any special adaptations for seed/fruit dispersal such as hooks or barbs, its seeds are small and often adhere to animal fur or clothing. Further, the fruits have been observed being transported on automobiles (Mehrhoff 2000).
relies entirely on its seed bank for its annual recruitment. Seeds of
may need a period of stratification (cool temperatures and high moisture) before they will germinate.
seeds stored in the soil may remain viable as long as five years.
seeds may have low germination rates
, but many seeds are produced by each plant. Seeds of
are also able to survive submersion in water for periods of up to 10 weeks. Barden (1991)
reports that seeds can germinate while under water, but the plants do not grow. If standing water is removed, more seeds will germinate shortly afterwards.
In the early 1900s,
was used extensively as a packing material for porcelain, especially fine China porcelain, which may have contributed to its invasion into the United States. Culms of this grass have also been used for basket weaving.
has not been documented as being intentionally planted as an ornamental, for erosion control, or for forage.
Potential for Restoration
Manual and mechanical, environmental/cultural, and chemical methods are all useful to varying degrees in controlling
. Prescribed burns have not been successful in controlling this species so far, but fall burns may have the potential for partial control.
produces a large number of viable seed that can remain in the soil seed bank for seven years or more. If controlled during the early stages of invasion, the potential for successful management is high. The potential for large-scale restoration of wildlands where
has become established is probably moderate.
The distribution of
should be monitored annually or biannually where there is a threat to protected species. Following all control treatments, further control efforts and monitoring is needed for at least seven years due to the viability of seeds in the seedbank or re-invasion from nearby propagule sources.
usually occurs in dense, nearly monospecific stands, permanent line intercepts (or transects) across population borders are an easy technique for periodic monitoring of changes in
distribution. Where it is less abundant, visual estimates of percent cover changes in permanent plots, or photographic documentation, carried out at the same (phenologic) time each year, may be for monitoring change over time. Additionally, new invasions of
should be identified as soon as possible, since small populations are the easiest to eradicate.
Manual and mechanical
Hand pulling of
is the preferred method of removal as it is highly specific and provides minimal impact (except trampling and soil disturbance) to the surrounding environment. Hand pulling is an effective method of control if it is thorough and timed correctly. It is, however, labor-intensive and time-consuming. Pulling late in the season (September-early November) before seed production reduces the unintentional spread of the current year’s seeds. Pulling early in the season (before July), however, allows germination of new plants from the seed bank which will mature during the remaining season and produce seeds. In the northeast, August and late September are good times to pull plants by hand.
Yearly weeding is necessary because new plants can appear as a result of seed banking or re-infestation from new seed being dispersed into the area.
Mowing using a weed whacker (or a weed-eater) is an effective control method if carried out in late summer just before seeds are produced. Mowing at any other time is not useful as the plants have the ability to resprout and can produce seed heads in the axils of their lower leaves.
Mowing can also be useful in reducing the amount of litter and plant biomass prior to herbicide application, making the herbicide more effective.
Grazing, flooding, burning, and biocontrols
Grazing is not a control option for
since cattle, deer, and even goats avoid feeding on it.
Flooding for more than three months, or intermittent flooding during the growing season, may be an effective control method for mature plants of
. The seeds of
, however, can survive periods of inundation of at least ten weeks.
Spring burns are ineffective at controlling
because a new cohort of seeds will germinate soon after the burn. Burns in the late fall, however, may be useful in controlling this species.
Burning is also useful in reducing the amount of litter and plant biomass prior to herbicide applications.
No biological controls are currently available for
For large infestations of
, the use of herbicides may be the only viable option for good control. A series of control experiments using herbicides was carried out at the Ames Plantation (University of Tennessee), and the researchers reported that it is relatively easy to kill
, but that managing for a desirable plant community is difficult. They found that the herbicide imazameth (tradename Plateau
) was the herbicide of choice for controlling
. This is because imazameth (applied at a rate of 6 ounces per acre) kills
, but allows the development of (a.k.a., does not kill) the desirable native sedges, ragweeds, and legumes.
The grass-specific herbicide fluazifop-p (tradename Fusilade
) applied at the rate of 1.2 liters per hectare (1 pint per acre) also controlled
, but left a less desirable plant community. Glyphosate (tradename RoundUp
) was also tested, but resulted in a complete kill of all plants, which could potentially lead to possible re-invasion by
or other undesirable species. Barden (1991)
also found glyphosate useful in killing
Formulations of glyphosate registered for use aquatic systems (Rodeo), has been effective for
control in wetlands. Woods (1989)
in Tennessee found that the grass-specific herbicide sethoxydim (tradenames Poast
), applied during late summer at rates of 1 pint per acre, also provided excellent (more than 95%) control of
and released dicots from competition without injuring them. Pre-emergent herbicides such as diphenamid (tradename Enide
) and benefin (tradename Balan
) have also demonstrated excellent control of
seedlings under conditions of good herbicide-to-soil contact
, but do not encourage the germination of native species.
Allan Houston (pers. comm.)
reports that if there is a heavy build-up of litter (dead plant material) in
stands, burning the debris may first be necessary to get adequate herbicide coverage. He suggests applying herbicide when the plants reach a height of 5-10 centimeters (2-4 inches).
According to TNC’s 1998 Weed Survey,
has been reported from TNC preserves in New Jersey, North Carolina, Virginia, Georgia, Alabama, Arkansas, Maryland, and in Connecticut. Several preserves reported
is one of their worst weed problems, but only a few had begun active control measures.
In Maryland, Donnelle Keech reported that burning is not effective in controlling
. In North Carolina, Robert Merriam reported hand pulling was effective. Elizabeth Farnsworth in Connecticut, however, indicated that hand pulling may be effective in small populations, but seems futile for large populations since it is difficult to eliminate the seed sources. She added that it is important to attack small infestations as soon as possible, and to attack them vigorously!
Elizabeth Farnsworth or David Gumbart
The Nature Conservancy
55 High Street
Middletown, CT 06459