fountain grass — Maui Invasive Species Committee (MISC)

Jared Clapper with Hāna Lima Land Management, working on behalf of Haleakalā Ranch, was part of a team responding to an infestation of invasive fountain grass in proximity to Pu‘uokali above Kīhei. Fountain grass has a reputation for fueling a cycle of brush fires and is one of the greatest threats to the remaining dryland forest ecosystems.

On the leeward slope of Haleakalā above Kīhei rises a red dirt cinder cone named Puʻuokali. Puʻuokali means “the hill of waiting,” and is said to be one of several mo‘o (lizard deities) who were transformed into cinder cones on the summit. From her prominent vantage, Puʻuokali watches over her daughter, Puʻuoinaina on the island of Kahoʻolawe. As visible as Puʻuokali is to Maui residents, she also has her secrets. Inside the cinder cone is an intact dryland forest – a representation of the most diverse and most threatened ecosystem in Hawaiʻi. This native oasis was forgotten about until the early 1980’s when a brush fire broke out nearby and biologists rediscovered the forest.

Dr. Art Medeiros, program manager for the Auwahi Forest Restoration Project, was one of those biologists. “Puʻuokali is amazing. It’s almost the only place from Makawao to Kaupō that looks like it did when Hawaiians were the only people here.” Wiliwili, lama, naio, koaiʻa, and ʻohe are the dominant trees of this forest – these plants were essential for early Polynesians but are virtually unknown today. Dryland Hawaiian forests are the most diverse of Hawaiian forests, yet they are virtually lost: an estimated 90 to 95% of dryland forest is gone. What remains is critical: 25% of endangered Hawaiian plant species are found in these tiny refugia.

In July of 2018, Byron Stevens of the Hawaiʻi Natural Area Reserves System passed over Puʻuokali in a helicopter and saw something that didn’t belong: a two- to four-foot-tall bunchgrass with wiry leaves and purple bottle-brush flowers. Fountain grass. He sounded the alarm to multiple conservation organizations.

Fountain grass starting to invade the sacred grounds of Puʻuokali on Maui. This area is one of the few remaining places that show how Hawaiʻi looked prior to western contact.

Fountain grass is an invasive weed rarely found on Maui. Native to North Africa, it’s targeted for eradication by the Maui Invasive Species Committee. The drought-tolerant grass is able to survive in some of Hawaiʻi’s driest areas; it poses a serious threat to native dryland forest. While rare on Maui, the alien grass now covers much of the leeward coast of Hawaiʻi Island. Introduced as an ornamental in the early 1900s, fountain grass has completely transformed the Kona side of Hawaiʻi Island, turning what was once bare lava with patches of native forest into fields of grass.

“Introduced as an ornamental in the early 1900s, fountain grass has completely transformed the Kona side of Hawaiʻi Island, turning what was once bare lava with patches of native forest into fields of grass.”

Dominating arid, bare lava is one thing, but this wiry bunchgrass can also advance into intact forest, in part because it survives brushfires. Fountain grass is fire-adapted; it can regrow after flames pass over then quickly flowers and set seeds to recolonize the area. In contrast, Hawaiian forests are not adapted to fires—native plants generally donʻt survive. Fountain grass is notorious for fueling and increasing fire. At one site on Hawaiʻi Island, fountain grass (ignited by humans) has increased fire frequency from once every 500-1,000 years to once every 6-8 years.

“Fountain grass is a direct threat to the Maui County sanctuary forests such as Puʻuokali, says Medeiros. Though surrounding areas have burned, Puʻuokali has not had any wildfire, hence why so much remains. This hidden forest survived over the years partly because the surrounding landscape was so barren. There was no fuel for brushfires, and less incentive for goats and deer to cross the cinder to reach the crater. “The last refuges [of dryland forest] are in these rocky areas,” Medeiros explains. The intrusion of fountain grass changes that.

Fountain grass is almost never found on Maui, but is extremely widespread on the leeward side of Hawaii island, where it has transformed the landscape and continues to spread. Any sightings of this invasive bunchgrass should be reported — identified by its purple bottle-brush flowers that turn white as they age. MISC file photo

With that in mind, crews from multiple organizations – Auwahi Restoration Group, Haleakalā Ranch, the Maui Invasive Species Committee, and the Plant Extinction Prevention Program – came together to remove over 1,000 fountain grass plants from Puʻuokali. Completing the work will take several years. Grass seeds cover the ground and recent rains will bring a flush of seedlings. But now that the infestation has been detected, it can be managed and eradicated.

You can help. Fountain grass is often used as an ornamental landscaping plant, and people sometimes plant it on Maui by accident. Seeds can be unwittingly transported interisland on hunting or golf gear. If you see fountain grass, take a photo and report it. You can contact MISC directly at 573-MISC (6471) or the statewide pest hotline at 643-PEST, or 643PEST.org.

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published in the Maui News on September 12th, 2018, as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Read more Kiaʻi Moku articles. Find more information about fountain grass:

Species profile: Fountain grass
Report suspected populations of fountain grass: 643PEST.org

Crew from Pūlama Lānaʻi and MISC partner to find the few invasive fountain grass plants present on Lānaʻi before they become a problem. Photo courtesy of Kari Bogner.

If you travel between the Hawaiian Islands you know that each Island is unique, in traditions and food, expressions and customs. Plants and animals vary also – both the native plants and animals as well as the invasive species that plague each island. Mongoose are not established on Lānaʻi or Kauaʻi. Miconia has never been found on Molokai. These differences reflect where pest species were introduced as well as the efforts to stop them.

On the island of Lānaʻi, Kari Bogner, Botany Program Manager with the Pūlama Lānaʻi Conservation Department, is tackling the eradication efforts of a half-dozen invasive plants that have been declared as lost causes on other Hawaiian Islands. Among them are parthenium, a weedy herb in the aster family; fountain grass, a fire-adapted grass from South America; and ivy-gourd, an invasive vine in the cucumber family. “I’m optimistic,” she says, “we’re making a lot of headway with these species.”

Eradicating a plant taxes the perseverance of even the most dedicated. Pulling, cutting, and digging is instantly gratifying, but returning week after week, month after month, searching for seedlings and waiting for the seed bank to be exhausted takes a toll on patience and budgets. The effort is essential – if a plant is missed and goes to seed, it starts the whole process starts again over. If those seeds are spread unnoticed, the setback is even greater.

In March of 2015, Maui-based botanist Hank Oppenheimer noticed a familiar weed outside of Lānaʻi City. It was the first time he had seen the pasture weed Parthenium hysterophorus (False ragweed) on Lānaʻi, but knew from his experience on Maui how invasive it was. Parthenium is native to the southern United States and Mexico. It is listed as one of the 100 worst invasive weeds in the world by the International Union for Conservation of Nature. Tiny seeds are carried unnoticed as people move cargo, animals, and soil long distances. Consequently, the pest has invaded 45 countries.

Parthenium takes over cropland and pasture, causing losses in the millions in Australia alone. The plant can inhibit the germination of other species – a survival strategy called allelopathy. This super-weed is not only poisonous to other plants–if it has invaded pasture, animals can be poisoned. Incidences of hay fever in humans also increase once parthenium invades.

False ragweed or *Parthenium hysterophorus* is too widespread to eradicate on Maui, but early detection efforts on Lānaʻi have contained the plant. Photo courtesy of Kari Bogner.

On Maui, parthenium is too widespread to eradicate, but on Lānaʻi, the pest is only known from one location. A five-person Pūlama Lānaʻi crew removed the plant from six acres. The weed can produce seed within four weeks of germinating so Bogner and Jerome Sunio, biosecurity tech with Pūlama Lānaʻi, return to check the site every 10-12 days to stay ahead of the seed cycle. She hopes to exhaust the seed bank soon – not a small task given that a single plant can produce 15,000 seeds. She has not found a seeding plant since April of 2018.

Fountain grass is also conspicuously absent on the pineapple island and not by accident. The invasive bunchgrass is widespread on the Kona side of Hawaiʻi Island, covering acres of lava and fueling wildfires that destroy native dryland forests and threaten homes. But on Lānaʻi, there are only a handful of places fountain grass has been found; crews from the Maui Invasive Species Committee (MISC) spent years seeking out and removing the ecosystem modifying weed and now Bogner and Sunio scour the last known site every two months looking for seedlings. This weed is also a MISC target for eradication on Maui and is not known from Molokai.

Spreading out across the hillside, crews form sweep line, searching for invasive fountain grass on on Lānaʻi. Fountain grass is a fire-promoting pest present on Hawai’i Island. Photo courtesy of Kari Bogner.

Ivy gourd is yet another Lānaʻi success story. The drought-tolerant vine from Southeast Asia threatens dryland forests and coastlines. The vine is beyond containment efforts on Hawaiʻi Island and Oʻahu. MISC controls it on Maui; it is not known to be on Molokai. On Lānaʻi, MISC found the fast-growing climber in a greenhouse, and seeds were inadvertently spread in potting soil throughout the Mānele area. After battling the climbing vine in bougainvillea and other plants, Bogner’s efforts to eliminate it are proving fruitful – or rather an absence of fruit – she hasn’t found a seeding plant since last year.

You can help. If you are on Lānaʻi, contact Bogner and Pūlama Lānaʻi at 565-3683 if you see parthenium, fountain grass, ivy gourd or anything new and unusual. If you travel back and forth, make sure your gear is clean and free of weed seeds and dirt that could spread pests interisland.

This article was originally published in the Maui News on October 12th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Fountain grass threatens dryland ecosystems

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