Species Management and Control Information

Japanese stiltgrass, Nepalese browntop
Microstegium vimineum (Trin.) A.Camus

GENERAL MANAGEMENT CONSIDERATIONS:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese stiltgrass- http://www.nps.gov/plants/alien/fact/mivi1.htm - Author: Jil Swearingen - September 10, 2004

A variety of control methods are available for stilt grass, depending on the extent of the infestation, the type of habitat, and the availability of labor and other resources. Preventing the introduction of stilt grass into non-infested areas and out of infested areas should be a priority. Early control of new infestations will also reduce the likelihood of establishment.

The Nature Conservancy - Species Management Summary (ESA): Japanese stiltgrass - http://tncweeds.ucdavis.edu/esadocs/micrvimi.html - Author: Mandy Tu - August 2000

Potential for Restoration of Invaded Sites: Manual and mechanical, environmental/cultural, and chemical methods are all useful to varying degrees in controlling M. vimineum. Prescribed burns have not been successful in controlling this species so far, but fall burns may have the potential for partial control. M. vimineum 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 M. vimineum has become established is probably moderate.

MANUAL AND MECHANICAL CONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese stiltgrass- http://www.nps.gov/plants/alien/fact/mivi1.htm - Author: Jil Swearingen - September 10, 2004

Manual: Stilt grass 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 stilt grass 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 stilt grass and may be difficult to distinguish from it. Because hand pulling plants disturbs the soil and may expose stilt grass 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.

Mechanical: Stilt grass 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 stilt grass 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 stilt grass plants cut early in the summer respond by and regrowing and flowering soon after cutting, much earlier than they would normally flower. Another reason to cut late in late summer to fall.

Southeast Exotic Pest Plant Council - Invasive Plant Manual - Bush honeysuckle - http://www.se-eppc.org/manual/japgrass.html -2003

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.

The Nature Conservancy - Species Management Summary (ESA): Japanese stiltgrass - http://tncweeds.ucdavis.edu/esadocs/micrvimi.html - Author: Mandy Tu - August 2000

Manual Control: Hand pulling of M. vimineum 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 (LaFleur 1996). 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 (G. Edinger, letter to J. Randall).

Mechanical Control: 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 (Woods 1989; Barden 1991). Mowing can also be useful in reducing the amount of litter and plant biomass prior to herbicide application, making the herbicide more effective.

Flooding: Flooding for more than three months, or intermittent flooding during the growing season, may be an effective control method for mature plants of M. vimineum. The seeds of M. vimineum, however, can survive periods of inundation of at least ten weeks (Barden 1991).

GRAZING:

The Nature Conservancy - Species Management Summary (ESA): Japanese stiltgrass - http://tncweeds.ucdavis.edu/esadocs/micrvimi.html - Author: Mandy Tu - August 2000

Grazing is not a control option for M. vimineum since cattle, deer, and even goats avoid feeding on it (A. Houston, pers. comm.; Barden 1991).

PRESCRIBED FIRE:

The Nature Conservancy - Species Management Summary (ESA): Japanese stiltgrass - http://tncweeds.ucdavis.edu/esadocs/micrvimi.html - Author: Mandy Tu - August 2000

Spring burns are ineffective at controlling M. vimineum 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 (Barden 1991). Burning is also useful in reducing the amount of litter and plant biomass prior to herbicide applications.

BIOCONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese stiltgrass- http://www.nps.gov/plants/alien/fact/mivi1.htm - Author: Jil Swearingen - September 10, 2004

The Nature Conservancy - Species Management Summary (ESA): Japanese stiltgrass - http://tncweeds.ucdavis.edu/esadocs/micrvimi.html - Author: Mandy Tu - August 2000

No biological controls are currently available for this plant.

CHEMICAL CONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese stiltgrass- http://www.nps.gov/plants/alien/fact/mivi1.htm - Author: Jil Swearingen - September 10, 2004

For extensive stilt grass infestations, use of a systemic herbicide such as glyphosate (e.g., Roundup) is a more practical and effective method. If applying glyphosate to stilt grass in wetland sites, use the formulation labeled for wetland areas (e.g., Rodeo). Apply a 2% solution mixed with water (8 oz. per 3 gals. mix) and a surfactant in late summer. Be careful to avoid application to non-target plants because glyphosate is a non-specific herbicide that will kill or damage most plant species it contacts.

Southeast Exotic Pest Plant Council - Invasive Plant Manual - Bush honeysuckle - http://www.se-eppc.org/manual/japgrass.html -2003

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.