pampas grass — Maui Invasive Species Committee (MISC)

Perils of pampas on West Maui Mountains

Posted on November 18, 2019 by Lissa Strohecker

Steve Perlman examining invasive pampas grass in Kauaʻula Valley. — MISC file photo

With plumes that bring to mind ostrich feathers, pampas grass first became popular in the Victorian era. Fluffy seed heads decorated the most fashionable hats, homes, even carriages. Interest surged again in the mid-1960s and the plant became a fixture in some yards and golf courses on Maui.

Today, pampas is taking over Instagram feeds: the plumes are used to add a Bohemian/Southwestern flavor to wedding bouquets, centerpieces, and home décor. But here on Maui, this ornamental grass is associated with a different trend: loss of habitat for threatened and endangered species and destruction of the watershed.

“But here on Maui, this ornamental grass is associated with a different trend: loss of habitat for threatened and endangered species and destruction of the watershed.”

Pampas can grow on nearly vertical slopes, displacing native plants that support populations of threatened and endangered animals and disrupting watershed function. With seeds that can travel 20 miles in the wind, ornamental plantings can infest far away forests. — MISC file photo

Pampas is a clumping bunchgrass native to South America. The leaves are razor-sharp, dying back each year but leaving dry foliage that accumulates and can fuel wildfires. The decorative plume is the seed-head and a single plant can spread millions of tiny seeds on the wind – in some cases, as far as 20 miles. Seeds germinate readily on bare soil, but with enough moisture, the invader finds footholds in patches of moss or tree bark. The plant competes with native vegetation and could replace habitat and food resources used by native birds and in doing so disrupting the layered structure of the rainforest so important for aquifer recharge.

This grass knows no limits – it has been found growing from sea-level to the rim of Haleakalā Crater at 9000 feet. Water, or lack thereof, doesn’t seem to be a key determinant for where pampas lives. It will (and does) grow in the wettest rainforests and on the driest hillsides, often emerging in rain-drenched bogs and wind-scoured cinder slopes.

Pampas grass has been a target for eradication on Maui since the mid-1990s when staff from Haleakalā National Park started finding feathery plumes in the crater. MISC has been working to stop pampas since the inception of the program. Through continued control efforts, the East Maui population has been in steady decline but without consistent support and control efforts, progress could stall.

MISC employee scoping out pampas. Invasive plants don’t always grow in easily accessible areas. The slopes of West Maui are so steep that efforts to remove plants like pampas grass necessitate the use of helicopters. — MISC file photo

The West Maui pampas population has always presented challenges. Much of the difficulty lies in the rugged terrain and weather, limiting access for much of the year. On East Maui, crews can access much of the known pampas infestation by timing helicopter flights early in the day and camping and hiking to access plants from the ground, but the slopes of the West Maui Mountains are more vertical than anywhere else in Maui, affording few camping sites and making ground access difficult or impossible. Pampas, on the other hand, thrives on the bare soil of the erosion-prone slopes. When that happens, our crews depend on helicopters to seek out and remove the invader.

Thanks to funding from the National Fish and Wildlife Foundation, MISC crews have been scouring the cliff faces of West Maui over the last year. They are looking for pampas plumes and the tell-tale growth pattern of the plant before it goes into flower. If they find the plant, they record the location by on a GPS and then return by helicopter but this time loaded down with an external tank and 80’ long line and weighted sprayer attached. This allows the pilot and crew to hold hover over the plant and remotely trigger a tiny spray of herbicide directly to the grass below.

Despite nearly constant rescheduling of flights due to weather or a need for the helicopters to go fight a brush fire, crews have flown over 15,000 acres on West Maui from 2017 to the summer of 2019. This coverage has led to the detection and removal of nearly 1,900 pampas plants from the mountain slopes– a huge leap forward in the effort to stop this invader from taking over prime habitat for native birds, plants, and invertebrates.

You can help. First, become familiar with what pampas grass looks like (mauiinvasive.org/pampas/). Second, never plant pampas grass or import it for décor or floral arrangements. The Division of Forestry and Wildlife has designated pampas as one of Hawaiʻis most invasive horticultural plants. Finally, report any pampas grass you find. You can report it to MISC: 573-6472, miscpr@hawaii.edu, or online at 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 14th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Pigs and Pampas

Posted on January 12, 2016 by Lissa Strohecker

A spike camp in the East Maui rainforest. Camps like these are home for the crews working to protect and remove invasive species in this remote section of Maui. Photo by Maui Invasive Species Committee.

At about 4000’ elevation, just east of Koʻolau Gap above Keʻanae on the island of Maui, a four foot tall hogwire fence stretches from the cliff edge across ravines and gulches to the next cliff edge at Honomanū. This fence and a rudimentary shelter are the only indications that people have ever set foot up here. It’s a unique section of the mountain; the soil is slow to drain and the ground is boot-sucking wet, even in summer. Clouds drift through the branches of ‘ōhiʻa all day long, leaving everything soggy, though rain may not actually fall.

The fence protects this section of East Maui rainforest from the feral pigs that roam farther down the mountain, but that was not always the case. Pigs are not native to Hawaiʻi. But until a decade ago, they wandered freely up here, miles from the nearest road. Though they weren’t plentiful, they did plenty of damage as they rooted through the soil, leaving patches of bare dirt scattered over hundreds of acres.

Pigs were not the only invaders. Pampas grass, an ornamental once planted in upcountry residents’ yards, sprang up throughout this forest. The tall, clumping grass sends up a feather plume filled with seeds that travel on the wind for miles. Pampas seeds occasionally germinate in mossy tree trunks, but their preferred conditions are bare soil with regular moisture. Pigs in Honomanū cleared and prepped the forest floor for pampas grass. Once a few plants became established, conditions were ideal for spreading. They quickly began to outcompete native species.

Far from the landscaped yards, pampas grass flourishes in the East Maui rainforest, benefiting from the disturbance created by another invader, pigs. Photo by Maui Invasive Species Committee.

Of course it’s not just pampas grass that benefits from the disturbance created by pigs. Many notorious invasives spread into upland forest with the help of wild pigs–strawberry guava and banana poka, for instance. Pigs carry the seeds in their gut, then deposit them with a pile of fertilizer. Their rooting habits create wallows for mosquitoes that spread diseases to native birds. Pigs knock down native hāpu;u tree ferns to reach a starchy meal in the trunk, in the process destroying the fern’s native seedling “nursery.”

In Hawaiʻi, pig impacts are magnified. The rototilling action of a pig is a completely alien force in a forest that evolved for millions of years without a hoof or tusk. “Disturbances to the forest floor from pigs and weed problems go hand in hand,” says Dan Eisenberg, who manages the East Maui Watershed Partnership. His organization built the fence east of Koʻolau Gap and other fences that protect high elevation forest on East Maui.

Fencing out pigs and other hooved invaders is the first step in restoring native Hawaiian ecosystems. When these tusked tillers are removed, plants do better–regardless of whether they are native or introduced. Common native plants recover in under a decade, but rare species often take much longer, and face competition from exotics that became established prior to pig removal. “Invasive plant species are so fast growing compared to most plants in the native forest that our unique native species don’t have a chance without responsible management,” explains Eisenberg.

As pigs dig for roots and grubs, they rototill the soil. Disturbance and bare soil creates gaps in the forest floor opening it up for invasive plants. Photo courtesy of East Maui Watershed Partnership

The East Maui Watershed Partnership completed the fence in Honomanū in 2006, about the same time, crews from the Maui Invasive Species Committee switched from trying to spray pampas from the air to camping in the field while removing pampas on the ground. Weeklong work trips are a less soggy ordeal since the team built a tent platform. When crews find pampas hiding amongst the native foliage, they cut off any seed heads, bury them inside the plant, and then kill the pesky grass in place, being careful to not disturb the soil and open up an area for seeds to germinate again.

During the summer of 2014, crews found and controlled 87 pampas plants, only 4 of which were capable of making seeds. Compare this with the summer of 2008, when crews found 2,029 plants. Pampas grass seeds don’t remain viable for long, perhaps as short as 6 months. Soon the East Maui pampas may disappear entirely and the forest can rebound.

Read more about the efforts to remove pigs and pampas grass on East Maui at www.eastmauiwatershed.org and www.mauiisc.org.

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.

Written by Lissa Strohecker. Originally published in the Maui News on October 11th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Make National Invasive Species Week Last All Year

Posted on February 24, 2012 by Lissa Strohecker Leave a Comment

National Invasive Species Week is February 26 to March 3 of 2012. While it’s great to pay attention for the week, here are a few simple actions, one for each month, to help make a difference on the invasive species front:

*Note: This list was originally published in the January 8th edition of the Maui News.

Start by removing invasive species in your own back yard, like this ornamental pampas grass.

January—check backyard first. Take a look in your own yard to see what invasive species you might be harboring– then remove ‘em! Backyards are often the source for plants and animals that escape to wreak havoc in our environment. If the plant or animal is a target for the Maui Invasive Species Committee, such as pampas grass or coqui frogs, call us and we’ll give you a hand.

February—be pest-savvy. The last week of February is National Invasive Species Awareness week. Take part by learning about a new invasive plant or animal and how to control or report it. Start at mauiisc.org, mauiinvasive.org, reportapest.org, or check for monthly editions of this column, then share what you know.

March—buy local—Maui local. Many pests are limited to just one island, but they spread when potted plants, cut flowers, equipment, even produce is moved between islands. Support Maui’s economy and protect our island by bringing home locally grown products. Avoid ordering seeds on the Internet as some plants may be invasive in Hawaii.

Clean your gear-boots, fins, packs, and cars-regularly to prevent the spread of hithchiking invasive species.

April—clean your gear. Headed out diving, snorkeling or hiking? Give your gear a thorough rinse or scrub to remove any hitchhiking seeds (check the tongue of your boots), algae, or insect eggs before you head out. And don’t neglect to check your car periodically, both the underside as well as the inside.

May—volunteer. You will meet interesting people and learn more about Maui. Many groups have weekend volunteer trips where you can lend a hand removing invasive species or planting native species. Find an organization at hear.org/volunteer/maui/

June—survey your yard for the little fire ant. This tiny ant often arrives unnoticed, but it can become a huge problem. Currently no known infestations exist on Maui, but there is a high likelihood they will arrive again. Surveying is as easy as peanut butter and a chopstick. Learn more at lfa-hawaii.org

July—travel smart. Check twice before you bring something interisland. Plants and plant cuttings must be inspected by the Hawaii Department of Agriculture before being taken interisland to ensure there are no unwanted pests or diseases riding along.

August—take a hike, but with new eyes. Public reports are one of the best ways we learn about new invasive species. So cruise around the neighborhood, or go for a walk in the forest. See a bird you’ve never seen before or a new plant that looks like it’s taking over? Take a photo and let someone know.

September—be neighborly. Some invasive species problems are too big to tackle alone, but left unchecked will become everyone’s problem. Offer to help out your neighbors with an invasive species in their yard.

Landscaping with native species, like this ālula, will also help save water. Photo by Forest and Kim Starr.

October—go native in your yard. Hawaiian plants have never been more available for landscaping. In addition to being a unique addition to your landscape, these species won’t be invasive and offer habitat for native animals. Another plus – these plants evolved to survive on rainfall, so when selected to match your climate, they can help you save water.

November—eat an invasive. The season of eating offers plenty of edible invasive species, from axis deer to pigs to. Make a meal, or part of a meal, in the spirit of removing invasive species. For more information (and recipes) check out invasivore.org.

December—celebrate in holiday style with an invasive pine tree. Each year Friends of Haleakala National Park and The Nature Conservancy lead December trips to remove invasive pines from areas in and near Haleakala National Park. Find details for the Friends trip at fhnp.org and for the TNC trip by calling 572-7849. Other trips may be listed in the newspaper.

This year make a resolution to help address invasive species— just one simple activity a month can add up to make a big difference in our community.

Article by Lissa Fox Strohecker

Originally published in the Maui News, January 8th, 2012 as part of the Kia‘i Moku Column.
You can find all the articles in the Kia‘i Moku series http://www.hear.org/misc/mauinews/

Pampas Grass: All Species on Maui are Invasive

Posted on November 28, 2011 by Lissa Strohecker Leave a Comment

Pampas grass plumes were once so popular they even decorated parade floats, such as this 1st prize winner in a parade in Colorado at the turn of the century. Photo courtesy of Denver Public Library, Western History Collection.

In the early 1870s an enterprising nurseryman in Southern California imported a tall, clumping grass with distinctive feathery plumes to his ranch. Over the next several decades he created an entire industry for the plumes of the plant called pampas grass. At the height of the plume boom, he was exporting 500,000 plumes a year throughout the United States and Europe, influencing Victorian-era fashion. By the close of the 19^th century, pampas plumes were dyed different colors to fill vases, decorate women’s hats, and cover parade floats. Eventually the trend ended, but pampas has been used in landscaping ever since.

This invasive grass is anything but fashionable. Now, rather than topping hats and decorating parade floats, the ten-foot-tall feathery plumes top clumps of razor sharp leaves throughout California. Pampas grass blocks beach access, fuels wildfires, and invades native ecosystems. Introduced to Maui in the 1920s, pampas has proven invasive here as well.

There are two species in Hawaii known as pampas grass, Cortaderia selloana and Cortaderia jubata. Both species of pampas grass have been planted widely in landscaping throughout California; now every backyard population has become a seed source for this invasive plant. Both species are also found on Maui and jubata has become extremely invasive. It finds a foothold in any bare soil or disturbed areas, and has invaded many different ecosystems from the dry rocky soil in Haleakala Crater, to the boggy rainforest of East Maui, and the eroded cliffs of West Maui. Control of jubata first began in 1989 by staff of Haleakala National Park and is continued by Maui Invasive Species Committee (MISC). Field crews attack pampas any way they can, hovering along cliffs with helicopters, camping in the rainforest for weeks, knocking on doors, and lining up across the slopes of Haleakala to search for the distinctive plumes.

But efforts to control the invasive Cortaderia selloana have been stymied by a confusion that began in California in the 1970s. When pampas grass was first recognized as being invasive, scientists thought C. selloana was only slightly weedy, whereas its cousin, Cortaderia jubata, was deemed to be an immediate and serious threat based on its ability to reproduce.

This stand of Cortaderia jubata plant, or pampas grass, was found in Haleakala Crater and removed in 2008. Pampas grass is an invasive species, and a variety thought not to be a local threat at one time has turned out to be one. Maui Invasive Species Committee photo.

A single jubata plant can readily produce fertile seed with no need for pollination. The downy light seeds float on the wind and jubata quickly escapes garden plantings. The selloana plant, however, requires both a male and female plant to produce fertile seed. Resource managers thought that only female plants were on Maui, making selloana a safe landscaping alternative to jubata because it wouldn’t be able to spread. But C. selloana turned out to be a wolf in plume’s clothing. A keiki selloana was found on Maui in 2006; the identification was confirmed by genetic analysis of a sample sent to the University of California-Davis, establishing that selloana is reproducing here.

Given evidence from California we can expect that selloana will be an even more aggressive invader than jubata. Over the past 60 years in California, the selloana population has expanded twice as fast as jubata. Selloana is increasingly able to invade native vegetation.

What was the “good” pampas in Maui backyards is now recognized as an invader lurking on the horizon. Please do not grow any kind of pampas grass on Maui. If you know of a population of pampas grass, or have it on your property, please call MISC (573-MISC) to have it removed free of charge.

Article by Lissa Fox Strohecker

Originally published in the Maui News, September 12th, 2010 as part of the Kia‘i Moku Column.
You can find all the articles in the Kia‘i Moku series http://www.hear.org/misc/mauinews/

Pampas Gone Wild-Haipua‘ena Part 3

Posted on November 23, 2011 by MISC Leave a Comment

In the final installment of the “Pampas Gone Wild” series, we’ll cover some of the key identification features of pampas grass that differentiate it from the native sedge, Carex. These features can also be used to identify immature pampas in other habitats.

There’s an immature pampas grass in this photo…any guesses?

Zoom in for a closer look.

A young pampas closely resembles a native sedge, Carex. First look for the flat leaf of pampas.

Compared that with the "corrugated" leaf of Carex.

Another key feature of pampas is the razor sharp serrated leaf edges, shown clearly in this photo. This feature is easy to find by running your finger carefully along the edge, even on very young seedlings.

This series was brought to you with the help of the above members of the MISC field crew, Summer 2011: Paul Gonzalez (SCA), Brooke Mahnken (GIS and Data Specialist), Chris Radford (Crew Leader), Matt Fairall (SCA), Frank Ritenour (SCA), and Abe Vandenberg (Field Crew and Outreach). Thanks for your good and muddy work out there!

If you think you have seen a pampas grass in Hawaii, please contact your local Invasive Species Committee. Many Mahalos!

Pampas Gone Wild-Haipua‘ena Part 2

Posted on November 21, 2011 by MISC Leave a Comment

Here’s a young, but mature, pampas grass in a mostly native rainforest…pulling this guy up will leave a big hole in the groundcover, a hole means a foothold for another invasive species, in many ways doing more harm than good.

But if we leave the plant alone we’ll continue to loose our watershed and native species to this high-threat invasive plant. How can we remove it? Keep reading…

1. Remove the seed-heads.

2. Tie the pampas in a knot. this is what we refer to as the “ponytail” method; bringing all the pampas leaves together makes it easier to treat and marks the plant as one we’ve treated.

3. Bury the seed-heads deep within the plant. This keeps the seeds from dispersing on the wind, likely how this plant arrived here in the first place.

4. With the seed-heads tucked away and the plant tied together crews can apply a low-concentration herbicide directly to the plant (another benefit of the ponytail method-no over-spray). Within a month the plant will be dead and beginning to decompose and native vegetation will be intact and poised to reclaim this patch of invaded rainforest. The location of each plant we control is recorded with a GPS so it can be monitored in the future to ensure no seedlings have germinated.

There you have it-how to control invasive pampas grass a native rainforest on Maui.

Stay posted to learn how to spot a pampas grass.

The sun sets on another day of field work in the remote rainforest of East Maui

Pampas Gone Wild-Haipua‘ena part 1

Posted on November 1, 2011 by MISC Leave a Comment

Pampas grass or Cortaderia jubata with it’s wind-dispersed seeds readily escapes cultivation. Tackling established populations far from civilization takes some work…check out the work in one of our remote field camps–Haipua‘ena.

Helicopters bring the gear and materials out for both the crew and for building a new platform out of the mud.

The crew prepares to start hiking in. Along the way they’ll be searching for pampas.

The boardwalk running along the Waikamoi flume…the easy part.

A dead pampas grass…excellent!

A not-so-dead pampas grass…not excellent.

Very lively and seeding pampas grass…euuuwwh

Check back to see how we treat pampas grass in this kind of environment!