(Schizachyrium microstachyum)


Hawai‘i-Pacific Weed Risk Assessment Score: 13 (High Risk); Visit for more info

Weed Fire Risk Score = 0.81 (This species is likely a high fire risk in Hawai’i); Visit for more information


  • Tall grass to 2 m (6 ft) that grows in dense clumps
  • Produces large, broom-like tufted seed heads
  • Native to tropical and subtropical America, introduction history unknown.
  • Unbranched below, freely branching above. Leaves 16 inches long by 0.3 inches wide. Inflorescences at stem terminals, loose, numerous spikes (racemes), light colored.


  • Thick growth displaces native plants.
  • Grows along roadsides, in disturbed areas and in open sites in shrub land and grassland.
  • Each plant produces millions of seeds that are spread by the wind, animals, vehicles and people.
  • Dry grass promotes fires and quickly regrows after wildfires.
  • Drought tolerant, yet is able to flourish in wetter areas


  • Unpalatable to goats and not regarded as an important forage grass.

In Hawaii:

  • Oahu: First collected on Schofield-Waikāne Trail in 2012.
  • Maui: First reported in Hāʻiku in 2022.
  • Molokai: None known
  • Lanai: None known
  • Kahoolawe: None known
  • Kauai: Widespread but relatively uncommon.
  • Big Island: Well established in lower pastures of Kahuku unit of Hawaiʻi Volcanoes National Park, Kaʻū District, where it was first collected in 1961.
  • Midway: None known
  • Naturalized along roadsides and in open sites in mesic shrubland and grassland, 210-1,310 m, on Kaua’i, O’ahu, Maui and Hawaiʻi. Primarily occurring in Hawaiʻi Volcanoes National Park


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