Hawaii Invasive Species Council

Fountain grass (Cenchrus setaceus, formerly Pennisetum setaceum)

Lava flow with fountain grass (Cenchrus setaceus) photographed above Kailua-Kona Airport, Kailua-Kona, Hawai‘i

Photo credit above: Eric Guinther (Wikimedia commons)

Fountain grass (Cenchrus setacceus) aside its look alikes: Red fountain grass and Feather grass

Photo credit above, left to right: Forest & Kim Starr, John Tann, Andre Carapeto

DESCRIPTION:

• Fountain grass is a perennial, clumping grass that can grow in a variety of habitats, from bare lava, to rangeland, to urban roadsides in drier areas of the Hawaiian islands (<50 in rain/yr).
• It can reach a height of 0.5-3 ft with a bristly, cylindrical shaped purple or rose-colored flower head that is 4-10 in long.
• Leaves are not flat “blades” like most leaves; they are long and round like wire.
• Originally native to Africa, it was introduced to Hawaiʻi as an ornamental plant and escaped from cultivation by 1914.

IMPACTS:

• The grass is an aggressive invader in dry parts of the islands, outcompeting other plants for water and space.
• “Poor pasture grass, degrades the quality of pasturelands, particularly in drier areas.” (MISC)
• “It disrupts the slows and natural process of lava fields changing into native forest.” (Plant Pono)
• It is fire-adapted and can survive brush fires that native plants will not. It also is fire promoting and and very excellent fuel for brush fires. 
• “Pennisetum setaceum is on the Hawaiʻi State Noxious Weed List. The Division of Forestry and Wildlife of the Hawaiʻi Department of Land and Natural Resources has designated this species as one of Hawaiʻi’s Most Invasive Horticultural Plants.” (Plant Pono)
• It is mentioned on Kauaʻi Invasive Species Committeeʻs (KISC) Black List which is, “39 plant species that are actively being controlled by one or multiple agencies on the island. These plants are managed or removed from federal, state, county, and/or private land.” 
• “Pono Endorsed Nurseries have voluntarily agreed to discontinue the sale of these plants. Any Kauaʻi residents with Black List plants in their yard are encouraged to have them removed.” (KISC)

ERADICATION & CONTROL METHODS:

• “Hand pulling of seedlings and plants every 1–2 months has been used with some success in Hawaii Volcanoes National Park.” (USDA, Forest Service)
• In many cases, mechanical removal such as with a mower or tilling may not be an option due to the rocky terrain fountain grass tends to grow on. In these cases it can sometimes carefully be cut back with a weed trimmer.
• Burning is not recommended as the grass grows back rapidly following fire. 
•  “Fountain grass mortality rates of at least 90 percent have been attained by the Lake Mead Exotic Plant Management Team of the National Park Service through the use of glyphosate spot treatments performed annually to actively growing plants.” (USDA, Forest Service)
• Seeds can remain viable but dormant for up to 6 years in soil, so long term management must be considered with any approach. 

WHAT YOU CAN DO:

• Do not plant fountain grass for landscaping or in your yard. Choose less invasive grasses, find more info at: https://plantpono.org/
• Remove fountain grass if it is found on your property as well as other invasive dryland plants. Doing this in areas where it is widespread can help create a firebreak to protect your home, especially in high risk, fire prone areas. 
• Report this species to 643pest.org or call 808-643-7378 (643-PEST) if seen on Oʻahu, Maui, Lānaʻi, Molokai, or Kauaʻi
• Decontaminate shoes/boots, hiking/camping gear and any other equipment when traveling from an island or area with heavy infestations of fountain grass (Such as North Kona)
• Decontaminate all high risk items to reduce interisland spread on Hawaiʻi Island (vehicles, cattle, horses, other livestock, feed, or soil/cinder)