What was once introduced as a useful pasture grass has become part of Hawaii's growing invasive-species and wildfire challenge. Guinea grass, a perennial species native to Africa, was brought to Hawaii during the 19th century because of its value as livestock forage. Over time, however, the grass spread beyond managed pastures and became naturalised across the islands. Today, its ability to grow into dense stands, produce thousands of seeds and rapidly recover after fire has made it a significant concern for land managers. A historical study, “From the Pasture to the Present: The History of Grass Introductions in Hawai‘i,” documents a successful introduction of Guinea grass by Judge McCully in 1883, with the grass reportedly first planted at a plantation in Kaʻū, Hawaiʻi. The study also records that by 1901, Guinea grass was widely used by the livestock industry. The Hawaii Invasive Species Council now lists the species as a high-risk invasive grass and gives it a 0.89 weed fire-risk score.
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