Japanese Stilt Grass
Microstegium vimineumPoaceae
Flower
Flower
Photos (c) Cheryl Comeau Beaton unless otherwise noted

Synonyms:

  • Nepalese browntop
  • Eulalia viminea

The Plant:

  • An annual grass reaching 6.5 feet tall, with numerous upright branches that resemble individual plants.

The Leaves:

  • alternate
  • light green
  • lanceolate
  • taper at both ends
  • slightly pubescent
  • silvery line on center of the blade, not pubescent

The Stem:

  • nodes and internodes glabrous
  • stems root at the nodes
  • give rise to long, branched, horizontal stems

The Flowers:

  • Green, grass-like flowers that mature to brown, growing in a terminal thick-branched panicle.

The Fruits:

  • elipsoid shape
  • caryopsis (grain)
  • yellow maturing to yellow-purple
  • late September through early October

The Habitat:

  • moist ground, open woods, wetlands
  • fields, paths, clearings
  • roadsides, gardens, disturbed areas
  • acidic to neutral soils that are high in nitrogen

Dispersal:

  • mechanically dispersed seeds
  • may cling to animals and people for long-distance dispersal
  • also spreads vegetatively when stems root at the nodes

Key ID Features:

  • alternate leaves
  • tapering at both ends
  • silver line on center of leaf blade

Similar Species:

  • White grass (Leersia virginica) is a perennial native grass that resembles Japanese stilt grass, but has an open panicle, no glumes, awnless lemma, hairy nodes, and scaly rhizomes. Japanese stilt grass is an annual with terminal spike-like branches, glumes, awned or awnless lemma, hairless nodes, and fibrous roots. White grass begins flowering in early to mid August and has a greenish fall color, while Japanese stilt grass begins flowering in mid-September and has a yellowish to pale purple fall color.

Notes:

  • Japanese stilt grass threatens understory vegetation because it can thrive in low light conditions. It produces many long lived seeds that can remain viable even after a fire. After a burn seeds can sprout and create a dense monoculture that can displace native vegetation
  • There are no confirmed occurences of this species on Nantucket as of December 2006. Several people have reported sightings in the past, but these have all turned out to be other species.

Growth Form: Grass

Origin: Tropical Asia

Level of Invasiveness for Nantucket: Potential Invasive

Level of Invasiveness for Massachusetts: Likely Invasive

Massachusetts Cultivation Restrictions: importation ban, propagation ban




Credits: The Electronic Field Guide to the Invasive Plants of Nantucket (c) 2005-2006 Maria Mitchell Association, EFG Project, UMass Boston