Japanese Stiltgrass Management in the Home Lawn and Landscape

Origin and Distribution

Japanese stiltgrass (Microstegium vimineum) is an invasive grass that threatens native plants and natural habitats in the eastern United States.  Native to Japan, China, central Asia and India, M. vimineum was originally documented in Tennessee in 1919 and is believed to have been accidentally introduced to the United States through its use as a packing material.

Stiltgrass thrives in moderate-to-densely shaded areas subject to regular soil disturbances, such as flooding, mowing, tilling, and high foot traffic.  Stiltgrass is commonly found along roadways and ditches, floodplains, moist woodlands, and power line corridors.  Stiltgrass often thrives in soils that are moist, acidic, neutral, and fertile.  Stiltgrass also severely threatens forests, especially along trails, forest edges, canopy gaps, and other areas of disturbance.  In residential areas, stiltgrass can invade lawns, landscape beds, and vegetable gardens.  While it is most prolific in moist, shaded areas, it is becoming more common to find it growing well in full sunlight and drier soils.

Biology and Identification

M. vimineum is an annual grass that germinates in the spring, grows to heights of 2 to 3½ feet, and dies back in the fall.  Stiltgrass is identifiable by its pale green, lance-shaped leaves that have a silvery stripe of reflective hairs along the midrib of the upper leaf surface (Figure 1).  The leaf margin also has a very fine, less conspicuous silvery edge.  The leaves are alternate and range in length from 1 to 3 inches.  Stiltgrass leaves resemble bamboo, but its stems are thin and wiry, and can be green, purple, or brown.  In August through early October, the plants generate slender flower stalks with one to three spikes.  After blooming, dry seeds are produced, which are yellow to red in color.  In the fall, the plants develop a purplish tinge.  At the end of the season, dieback of the plant produces a thick layer of dried, tannish thatch in heavily infested areas (Figure 2).

M. vimineum exhibits several traits common to invasive species, such as rapid growth, abundant seed production within one season, and rapid invasion of disturbed habitats.  Stiltgrass grows in extensive patches, displacing native species.  The roots of stiltgrass are shallow, but rooting from stem nodes that touch the ground facilitates its spread (Figure 1).

Each plant can produce up to 1,000 seeds from both self-fertilizing and cross-fertilizing flowers.  Once in the soil, seeds can remain viable for up to 5 years.  The seeds are small and easily adhere to clothing, shoes and animal fur, which aid the spread of M. vimineum along woodland pathways, lawns and gardens.  Deer and other grazing animals further enable infestation by feeding on native plants and avoiding the stiltgrass, while dispersing stiltgrass seeds.  Additionally, overgrazing of the forest understory by deer removes plant competition, facilitating the invasion of M. vimineum.  Once established, M. vimineum may impact surrounding plants by increasing shade, crowding, and altering soil chemistry.  Left unchecked, native vegetation in susceptible areas can be overtaken in three to five years.

Several native species resemble Japanese stiltgrass, so before applying any control, it is important to correctly identify Microstegium vimineum.  Native species that stiltgrass can be confused with include:

1. Crabgrass (Digitaria spp.) has darker green foliage, longer and narrower leaves lacking the silvery midvein of stiltgrass.
2. Nimblewill (Muhlenbergia schreberi J.F. Gmel.) is a perennial grass with very slender leaves lacking the silvery mid-vein and has fine stems.
3. Virginia cutgrass and rice cutgrass (Leersia spp.) are perennial grasses with longer, slender leaves lacking a silvery mid-vein, and with notably abrasive texture capable of cutting unprotected skin.
4. Rosette panicgrass (Dichanthelium spp.) are perennial grasses with an appressed basal rosette and leaves up the stalk lacking silvery mid-veins; florets appear in multi-branched, pyramidal panicles.
5. Smartweeds (Persicaria spp.) are flowering herbs with pink or white calyxes and glossy black nutlets; stems have notable sheaths at each node.  Leaves usually have a white slender mid-vein, but not silvery.

Management

Early control of new infestations and preventing the drop of viable seed are critical for preventing the establishment and spread of Japanese stiltgrass.  Small populations are fairly easy to eradicate with hand pulling.  Large populations likely require herbicide treatment.  There are no known biological control methods.

In Lawns

Cultural Control

Growing and maintaining a healthy, dense lawn is the best preventative method to discourage the introduction of and growth of Japanese stiltgrass in turfgrass.  Proper seed selection, mowing, liming and fertilizing according to a soil test, watering, etc. are all important cultural practices for maintaining healthy turfgrass (Refer to the Rutgers Cooperative Extension website or your local County Extension Office for more information on maintaining a healthy lawn).  Note that routine mowing of stiltgrass in a lawn area will cause stiltgrass to set seeds at a low height.  If the stiltgrass does set seed in mid to late summer, very low mowing and bagging of the clippings may help to collect some of that seed and prevent it from being deposited into the lawn.  Keep in mind that very low mowing can also damage desirable turfgrass species, and overseeding may be needed to re-establish lawn cover.

Mechanical Control

Hand pulling can be effective for control of small infestations of Japanese stiltgrass.  It is important to remove it before the seed is dropped (~ mid-August in NJ).

Chemical Control

Preemergence Herbicides

The same herbicides that can be used to prevent crabgrass in a lawn (dithiopyr, prodiamine, and pendimethalin) can also be used to prevent Japanese stiltgrass.  However, these preemergence herbicides need to be applied about a month earlier than they do for crabgrass control.  In southern NJ, an ideal application timing would be in early March.  In northern NJ, it would be mid to late March.  This is because stiltgrass germinates about a month earlier than crabgrass (Figure 3).  If they are applied after stiltgrass emergence they will not be effective.  For more detailed information on these materials homeowners should see Rutgers Cooperative Extension Fact Sheet FS1308, Crabgrass Control in Lawns for Homeowners in the Northern US, and landscape professionals should refer to Rutgers Cooperative Extension Fact Sheet FS1309, Crabgrass and Goosegrass Identification and Control in Cool-Season Turfgrass for Professionals.

Postemergence Herbicides

Fenoxaprop-p-ethyl (trade names include Acclaim® Extra and Bioadvanced® Extreme Crabgrass Killer) is the most effective herbicide for Japanese stiltgrass control after it has emerged.  Other herbicides commonly used for postemergence annual grass control (for example, mesotrione and quinclorac) are not very effective.  Fenoxaprop-p-ethyl is most effective when Japanese stiltgrass plants are small and not as noticeable during April and May.  Carefully scout areas with a history of Japanese stiltgrass in April and May to determine where to apply.  As plants get larger, fenoxaprop-p-ethyl becomes less effective, and multiple applications will be needed for control.  Fenoxaprop-p-ethyl can be used on established perennial ryegrass, tall fescue, fine fescues, and Kentucky bluegrass.  Stunting or discoloration may occur on succulent, rapidly growing, and seedling Kentucky bluegrass turf, but these symptoms will subside if precautions on the label are followed.  Do not mix with the broadleaf weed herbicides 2,4-D or MCPP, (or apply within 21 days following application of 2,4-D or MCPP or 5 days before 2,4-D or MCPP application).  Fescues and ryegrass can be reseeded at any time following the application of fenoxaprop.  Reseeding of all other turf grasses should be delayed at least 21 days after application.  This herbicide will be less effective if applied when Japanese stiltgrass is drought stressed.  If desirable turfgrass or Japanese stiltgrass is wilting during the day, wait to apply until rainfall or irrigating the site.

In Landscape Beds

Mechanical Control

Hand hoeing and hand pulling can be an effective means to control stiltgrass as long as it is done before it has dropped seed (~ mid-August in NJ).  Recognize that hoeing or pulling stiltgrass early in the season (before August) disturbs soil which can stimulate germination of new plants from the seed bank.  Just as in lawns, constant cutting will cause stiltgrass to grow at a lower height but still set seeds.  A more successful control strategy is to trim plants just before flowering (~ early August in NJ) which cuts off the flowering culm before seed matures.

Cultural Control

Various mulches can be used to exclude light from the soil and keep stiltgrass from germinating.  If used in conjunction with preemergent chemical controls (see below), apply the preemergent herbicide before fresh mulch is spread.

Chemical Control

Preemergence Herbicides

Japanese stiltgrass is one of the first summer annuals to germinate in the spring.  These preemergence herbicides need to be applied before stiltgrass germinates as the soils warm in the spring.  Germination typically starts in early-mid March in southern NJ and mid-March to early April in northern NJ.

Trifluralin (Preen Garden Weed Preventer® and Treflan®) can be used to prevent stiltgrass seeds from germinating in planting beds.  Trifuralin must be applied according to the label; it should not be used in areas in which ornamental flowers will be directly seeded into the soil (as opposed to transplanted into the area).

Pendimethalin (Pendulum® and Prowl®) for use by landscape professionals only.

Postemergence Herbicides

Postemergence herbicides are most effective when applied before plants set seed.

Glyphosate and Glufosinate (various trade names) can be used to spot treat Japanese stiltgrass in gardens and planting beds.  Both are broad spectrum herbicides that should be applied only to unwanted plants.  If applied to the foliage, stems, or woody portions of desirable plants, it could damage them as well.

Sethoxydim (Bonide Grass Beater Over-the-Top Grass Killer®) and fluazifop-P-butyl (for example, Ortho Grass B Gon Garden Grass Killer®) are selective herbicides that can be applied to growing stiltgrass in landscape beds.  When used according to the label, these herbicides will not damage most non-grass ornamental plants.  Be sure to follow the label closely and heed all precautions.  If plants are large when treated, they may survive one application.  Treat again if regrowth is observed more than 3 weeks after application.

Fexoxaprop-p-ethyl (Acclaim® Extra), imazapic (Plateau® and Cadre®), sethoxydim (Segment® II, Poast®, and Vantage®), fluazifop-P-butyl (Ornamec® and Fusilade® II), clethodim (Select®), and quizalofop (Assure® II).  If plants are large when treated, they may survive one application.  Treat again if regrowth is observed more than 3 weeks after application.

References and Resources

1. National Invasive Species Information Center: Japanese Stiltgrass.  United States Department of Agriculture.
2. Invasive Plants in Pennsylvania.  Japanese Stiltgrass (Microstegium vinineum) (PDF).  Pennsylvania Department of Conservation and Natural Resources.  2pp.
3. Japanese Grass or Eulalia - Microstegium vimineum.  Southeast Exotic Pest Plant Council (SE-EPPC). 2003. Southeast Exotic Pest Plant Council Invasive Plant Manual.  Developed by the Center for Invasive Species and Ecosystem Health at the University of Georgia.
4. New York Invasive Species Information.  The New York Invasive Species Clearinghouse.  Cornell Cooperative Extension Invasive Species Program.  Japanese Stiltgrass (Microstegium vimineum {Trin.} Camus).
5. Introduced Species Summary Project: Japanese Stilt Grass (Microstegium vimineum).  Center for Environmental Research and Conservation, Columbia University.

This is based on the original work of Pat Rector, Environmental and Resource Management Agent, Morris and Somerset counties, Retired.

Photo credits for images across top:
Left: Japanese Stiltgrass mixed in with lawn grass – Photo credit: Peter Nitzsche
Center: Japanese stiltgrass growing tall next to a bench - Photo credit: Peter Nitzsche
Right: Japanese stiltgrass patch zoomed into leaves for identification – Photo credit: Jean Epiphan

March 2026