Presentation on the invasive Japanese stiltgrass.

1. Japanese Stiltgrass
Microstegium vimineum
Chris Evans
River to River CWMA
www.rtrcwma.org/stiltgrass

2. Japanese Stiltgrass
• Nepalese Browntop, Eualia, Chinese Packing
Grass
• Annual, warm season, shade tolerant grass
• Native to Asia
• First found in the United States in 1919 in
Knoxville, Tennessee

4. Identification
• Weak rooted annual
– Pulls up easily
• 1-6 feet in height
• Sprawling, weak stems
• Longer stems prostrate along ground or
propped-up

7. Identification
• Turns purple-brown in fall, starting at the top
of the plant (hence the name ‘Browntop’)

8. Identification
Leaves
• Short, wide leaves
– 2-4 inches long
– ½ - ¾ inch wide
• Whitish midrib
• Smooth edges (not
serrated)

9. Identification

10. Identification
Flowers/seeds
• Thin spike-like raceme
• 1,2 or 3-branched on long,
wiry stem

11. Ecology
• Grows in a variety of habitats
– Deep shade to full sun
– Moist soils to dry conditions
• Does best in semi-shaded environment with
adequate soil moisture
• Seeds can be viable for a long period (7-10
years), but most germinate in first two years
– Differs by seed type and local conditions

12. Ecology
• Invade forests, forest edges, roadsides,
ditches, etc.
• Has the ability to dominate forest understory
plants
• Spring fires seem to
promote stiltgrass

13. Impacts
• Decreases habitat/forage
• Decreases diversity in forest
understory
• Restricts some tree seedling
establishment
• Increases fuel loading

14. Timing
• Late spring – seeds germinate
• Summer – peak growth
• Late summer / early fall – flowering
• Early fall – seed set
• Mid-late fall – senescence

16. Japanese Stiltgrass

20. Spread
• Still actively expanding its range
– Water
– Gravity
– Animals
– Humans
• Equipment
• Roads
• Shoes
• Materials

23. Spread
• Stiltgrass closely follows disturbance
– Logging roads
– Fire breaks
– Trail construction
– Logging
– Other invasive control

24. MANAGEMENT AND CONTROL

25. Management and Control
• Easy to kill, hard to eradicate
• Pulls easily
• Variety of herbicides work
• Mowing before flower initiation
• Fall burns?

26. Chemical Control
• Broad-spectrum, grass-specific, and pre-
emergent herbicides will kill stiltgrass
– Some recent research indicating that native
recovery may be best when using grass-specific
herbicides
• Wetlands and streamsides limit what type of
chemicals you can use
– Aquatic-label glyphosate

27. Chemical Control
• Sethoxydim
– 1-1.5%
• Fluazifop
– 0.5%
• Clethodim
– 0.33-0.66%
• Glyphosate
– 1-2%

28. Mechanical Control
• Post-treatment equipment sanitation is a
MUST
• If flowers are present, then plant material
should be bagged and removed
• Late summer (but before flower initiation)
mowing may prevent seed set

29. Management and Control
• Key is to conduct control efforts before flower
initiation or seed set
– Being an annual, your goal is not to kill the plant, it is to
prevent seed production
– Germination may continue after early-season control
activities
• Think about landscape level infestations
• May be a waste of money to control stiltgrass in one
area if infestations occur farther upstream in the
watershed

30. Prevention
• Early Detection / Rapid Response
• Equipment sanitation
• Infestation avoidance
– Re-routing firebreaks
– Pre-logging treatments
• Changes in firelines
– Green lines
– Blown instead of plowed lines
• Coordinate efforts regionally

31. Summary
• Stiltgrass is a major invader of forestlands with
drastic impacts
• Stiltgrass has rapid spread and can be introduced
through human activities
• Several different chemical treatments are effective at
controlling stiltgrass, but grass-specific herbicides
tend to allow recovery of native plants the best
• Coordination across ownership boundaries is
necessary to achieve success in management