Maui Invasive Species Committee (MISC)

Mullein

(Verbascum thapsus)

Family: Scrophulariaceae

Considered very invasive and is on the Hawaii State Noxious Weed List.
The Division of Forestry and Wildlife of the Hawaii Department of Land and Natural Resources has designated this species as one of Hawaii’s Most Invasive Horticultural Plants.

Description:

  • Herbaceous biennial that reaches up to 10′ tall by its second year.
  • Large oval-shaped leaves range in size from 3-20″ long and 1-5.5″ wide. Covered in dense woolly hairs.
  • Sends up a flower stalk in the second year reaching 10′ tall, clusters of small yellow flowers grow in a random fashion along the stalk.
  • Native to Europe, mullein is naturalized in temperate ares of the world and has been intentionally cultivated for its medical properties.

Harm:

  • Quickly colonizes disturbed areas and out-competes native vegetation.
  • Produces numerous seeds that may remain dormant for over 100 years.
  • Drought-tolerant and able to withstand cold, mullein could invade native alpine ecosystem in Hawaii in places like Haleakala

In Hawaii:

  • Hawaii Island – Common on leeward uplands 3,940-9,840 ft of Mauna Loa, Mauna Kea, and Hualalai. It occurs also occasionally occurs in areas outside these zones, including windward Mauna Loa and some coastal and arid western sites.
  • Maui – First discovered in 1986 at over 9,000′ on Haleakala. It has since been found culitvated at several locations in Kula, all known locations are under active control and surveillance.
  • Not known from Kauai, Oahu, Molokai, Lanai, and Kahooolawe.

Little Fire Ant

Find aerial treatment schedule for Nahiku here: Nahiku LFA Aerial Treatment

Little Fire Ant (Wasmannia auropunctata)

Family: Formicidae

Since the discovery of Wasmannia auropunctata on the Hawaiʻi Island in 1999, the Hawai’i Department of Agriculture (HDOA) worked closely with the local invasive species committees (including MISC), as well as the United States Fish and Wildlife Service to prevent the further spread of this ant species. The Hawaiʻi Ant Lab, a project of the Pacific Cooperative Studies Unit, is also working diligently to mitigate the threats and prevent the inter-island and intra-island spread of existing invasive ant species, including the little fire ant.

Description:

  • This ant is orange-red to light brown in color, all workers are 1.5 mm in length (half the size of a sesame seed, or as long as a penny is thick, about 1/16 “)
  • Slow-moving, easily dislodged from leaves, plants, and trees
  • Prefers moist conditions, forming colonies on the ground AND in trees
  • Native to Central and South America, LFA were accidentally introduced as hitchhikers on imported plants

Harm:

  • Delivers a painful sting when disturbed. Welts can last for weeks
  • Infests agricultural fields and farms, where they damage crops and sting workers
  • Promotes plant pests such as aphids, white flies and scale insects, which secrete plant sap that the ants eat. In turn, the ants protect these insects from natural predators and parasites.
  • Easily blown out of trees, stinging when they get are caught in hair or clothing.
  • Infests homes, beds, furniture and food
  • Has been linked to corneal clouding and blindness in pets
  • In the Galapagos, LFA attack tortoise hatchlings and sting the eyes of adult tortoises
  • Infest bee hives, preying on the larvae and eventually destroy the hive.
  • Large infestations are difficult and expensive to control

On Maui:

  • First detected on Maui in October of 2009 in Waiheʻe. Thanks in part to the early detection of the infestation, an extremely cooperative landowner, and the recently formed Hawaiʻi Ant Lab,  the 1/3 acre infestation was eradicated.
  • December 2013:  a Maui resident discovers LFA in hapuʻu logs purchased from a local garden shop. Trace-back efforts by HDOA uncover infested material shipped several places in the state.
  • June 2014:  a MISC employee surveying for LFA discovers an extremely small population of LFA in a South Maui hotel.
  • September 2014: MISC field crews working to control miconia find a 20+ acre infestation in a densely vegetated area near Nahiku.
  • January 2015: a Maui resident reports stinging ants to MISC. Delimitation surveys reveal a 5-acre infestation in Huelo and ants moved to a single location in Haʻikū.
  • Early detection and prevention are essential and the public is urged to report unusual ants on Maui to MISC at 573-6472 or HDOA at 643-PEST.
  • All known infestations have been or are currently being controlled. MISC partners with HDOA and Hawaiʻi Ant Lab in detection and control efforts, as well as public outreach activities to raise awareness about LFA.
  • MISC’s management goal for little fire ant is island-wide detection and eradication.

Pest Alerts and Publications:

For more information, see:

Premiere of the new documentary Invasion: Little Fire Ants in Hawaii

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LFA Premiere invitationIn 2009, Waihee farmer Christina Chang was stung on the eye by a tiny ant at her home on Maui. She suspected, and the Hawaii Department of Agriculture confirmed, that this ant was the little fire ant, Wasmannia auropunctata, never before found on Maui. The detection spurred creation of a new documentary, Invasion: Little Fire Ants in Hawaii.

Invasive species introductions to Hawaii often end in regret and a list of should-haves. This film, produced by the Maui Invasive Species Committee, aims to change the result of the arrival of little fire ants in Hawaii. Featuring videography from award-winning film makers Masako Cordray and Chris Reickert, this half-hour film examines the biology, impacts, and potential solutions to the spread of little fire ants through interviews with scientists, farmers, and community on the Big Island reeling from the impacts of this miniscule, but devastating, ant. Viewers will learn how to identify and report new infestations, helping to protect Hawaii from this small stinging ant

The Waihee site is on target for eradication. However, little fire ants have recently been detected moving between islands, raising concern about the establishment of new infestations. On Hawaii Island, the little fire ant is now widespread in the Hilo area where efforts are focused on educating landowners about control options.  Infestations are now occurring on the Kona side as well. Research on effective control continues by the Hawaii Ant Lab, a joint project of the Hawaii Department of Agriculture (HDOA) and University of Hawaii. The little fire ant on Kauai is contained within a 12-acre area under active control by HDOA

The film will premiere on Maui January 8th at the McCoy Theater at the Maui Arts and Cultural Center. Doors open at 5pm. An awards ceremony and panel discussion will follow the screening. Food and beverages are available for purchase on site beginning at 4:30pm.

Screenings on other islands will follow. Please RSVP to miscpr@hawaii.edu to reserve a seat. Below is the current screening schedule:

  • Maui: January 8, McCoy Theater and the Maui Arts and Cultural Center, 5pm
  • Oahu: January 13, Cafe Julia at the YWCA, 1040 Richard St, 4:30pm
  • Kauai: January 18, Kauai Community College Performing Arts Center
  • Hilo: TBA (February 18)
  • Kona: February 19, Aloha Performing Arts Center, 5pm

The film will also air throughout the state on KITV

Sat 1/11                630-7PM

Sunday 1/12       9-9:30AM

Sat 1/19                4-4:30PM

Sunday 1/20       10:30-11P

Funding and support for the film was provided by the Hawaii Department of Agriculture, County of Maui-Office of Economic Development, US Fish and Wildlife Service, Hawaii Community Foundation-Pikake Fund, Maui Electric Company, Alexander and Baldwin Foundation, Tri-Isle RC&D. MISC and the Hawaii Ant Lab are collaborative projects of the Pacific Cooperative Studies Unit.

Maui Activities for Invasive Species Awareness Week

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It’s Hawaii Invasive Species Awareness Week and on Maui, we’re focusing on ant awareness (more activities to follow).

What do you know about the little fire ant?  Here’s a change to test your knowledge and win some great prizes. Teachers-here’s an activity for you and your students!

Tune into KPOA 93.5 & KISS 99.9 March 4-8th for the Spot the Ant & Stop the Ant contest  from the Maui Invasive Species Committee and the County of Maui.

Be ready to answer the trivia questions (all information from stoptheant.org) on-air for a chance to win one of these great prizes from our sponsors:antcostumeweb

*Special thanks to the Hawaii Islands Land Trust

Think you have little fire ants on your property?
On Maui test & send in a sample to Maui Invasive Species Committee, PO Box 983, Makawao, HI 96768

From Paper Maps To GPS Units, The Evolution of Technology in Conservation

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GPS-enabled field computers help pilots and crews record where they've already surveyed and where they need to go.

GPS-enabled field computers help pilots and crews record where they’ve already surveyed and where they need to go.

If smart phones, tablets, and global positioning systems (GPS) are on your wish list, you are not alone. These gadgets are proving essential in the efforts to protect native Hawaiian ecosystems.

Accurate mapping has always been crucial to surveying for and controlling invasive species. Back in the mid 1990s Maui field crews first began finding miconia. Though not very long ago, the technology available then seems pre-historic today. Using altimeters and orienting from known physical landmarks, they would record plant locations by drawing dots on photocopies of topographic maps. These paper maps were filed away for future use. Subsequent visits meant more hand-drawn maps. Sometimes the only way to find a specific locale was to bring along someone who had been there before.

Early attempts to create electronic maps involved scanning topographic maps into a computer and then drawing dots to estimate locations using computer programs intended for design and drafting. There was an electronic record, but it was time consuming to create and not especially accurate.

Then along came the GPS, promising a precise reading of position and time anywhere on earth, in any type of weather, provided the receiver had an unobstructed view of 4 satellites.  Early GPS units were expensive and heavy. Accuracy was, well, not all that accurate.  That unobstructed view of satellites was often hard to come by given terrain and canopy cover—especially in Maui’s dense rain forest, where miconia was spreading. To record a position, field crews carried a pole that they had to piece together and snake up through the overhanging tree limbs. With luck and patience, they could get enough satellites to provide a reading and not lose the antennae in a tangle of branches.

Rather then depending on paper maps and memory, field crews now load maps onto GPS units that allow them to record where they control plants and guide them to where they need to search.

Rather then depending on paper maps and memory, field crews now load maps onto GPS units that allow them to record where they control plants and guide them to where they need to search.

GPS receivers have improved dramatically. Now field crews load maps onto GPS units and follow pre-recorded trails to locate remote populations of invasive plants.  Rather than relying solely on the memory of a few people, crews can be dispatched to remove plants even if no one among them has visited the area before. Hand-drawn maps are a thing of the past, transforming an unwieldy stack of maps into a few digital files, making it possible to track work on hundreds of thousands of miconia plants.

Helicopters survey vast areas for invasive plants while flight lines are recorded on GPS units to ensure thorough coverage. Spotters in the aircraft record precise locations of plants so crews can revisit the locations either on the ground or by air.  Each helicopter has a GPS-enabled field-rugged laptop loaded with maps to help guide the pilots and spotters.

Even flight following has changed dramatically. Pilots and crew used to have to stop what they were doing and radio in every 20 minutes to let managers know they were safe. Often, terrain blocked radio calls and pilots had to spend valuable time flying to an area where they could make contact. Now flight followers back at headquarters can monitor the helicopter’s whereabouts and status using a computer program synchronized with the GPS unit on the aircraft.

Technology has helped to increase efficiency and effectiveness of field crews on Maui and now these tools are in the hands, or pocket, of anyone with a smart phone. While plans are in the pipeline for invasive species reporting apps specific to Hawai‘i, there are many other options for reporting invasive and rare native species. If you are a cell-phone shutterbug you can easily send photos to email addresses-just type in an email where you would normally enter a phone number. You can also report online via the reportapest website at reportapest.org.  So next time you see plant or animal that causes you to raise an eyebrow just snap a photo and send it in and stay posted for future tools to help you learn more about the plants and animals in your backyard.

By Lissa Fox Strohecker. Originally published in the Maui News, December 9th, 2012 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.
You can find all the articles in the Kia‘i Moku series http://www.hear.org/misc/mauinews/

Fast-growing ivy gourd threatens rare dryland ecosystem on Maui

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Ivy gourd can be identified by the 5-petaled flowers and green fruit that turn red as they ripen, hanging like Christmas lights from the plant. Photo by MISC

Ivy gourd can be identified by the 5-petaled flowers and green fruit that turn red as they ripen, hanging like Christmas lights from the plant. Photo by MISC

On Maui, we are lucky to have so many open spaces.  Our island is relatively undeveloped, though you may beg to differ when you’re stuck in traffic.  The majority of the population lives along the coastlines.  This distribution of island residents is nearly identical to the distribution of ivy gourd; a highly invasive vine found growing in central, south, and west Maui.  And, as development expands, so does the population of ivy gourd. This is no coincidence.

Native to Africa, India, and Southeast Asia, ivy gourd was probably brought to the Hawaiian Islands by an immigrant from one of those areas.  The immature fruit of the plant, as well as the young shoots, are used in cooking.  Many recipes from Southeast Asia call for ivy gourd.  While it may taste good in a stir fry, it’s in poor taste—illegal even—to have the plant growing in your yard.

Inevitably, the vine escapes cultivation. Humans—and their pesky rodent counterparts—have been the vectors for spreading ivy gourd.   Rats scamper off with a stolen fruit spreading the seeds.  In absence of the insect pests that limit ivy gourd’s growth in its native habitat, the plant grows unchecked.  Roots form every time the branching vine touches the ground.   Each root is enlarged, giving ivy gourd the ability to survive lengthy periods of drought.

Ivy gourd, Coccinia grandis, can be hard to identify without the flower or fruit present.  The leaves are broad and flat, shaped like an angular heart, about 2.5 inches wide. They are arranged in an alternating pattern along the vine.  The flower is white, with 5 petals curving out of a tube-like base.  If the plant reaches the fruiting stage, the 3-inch long fruit, dangling like bright red Christmas lights, is a dead giveaway that the vine smothering your yard is ivy gourd.

Ivy gourd is fast-growing.   While we don’t know the actual rate of growth on Maui, it is a member of the cucumber family of plants that may grow up to 4 inches a day.  If we ignored this aggressive growing vine what would happen?  “We’d be ivy gourdians” a 7th grade student so aptly replied during a class visit by MISC. When people don’t consume ivy gourd, ivy gourd consumes the environment around us.  Trees, power poles, fences, even cars disappear beneath a mountain of vines.

The fast-growing ivy gourd can easily smother trees, fences, and power lines

The fast-growing ivy gourd can easily smother trees, fences, and power lines. It could transform the native dryland ecosystem, choking out rare Hawaiian plants and leaving nothing but curtains of green. Photo by MISC

Ivy gourd is currently limited to residential areas on Maui.  MISC’s successful control of the population depends entirely on the cooperation of property owners and residents.  Because the vine grows so fast, and because the seeds germinate so quickly after a rain, monthly site visits may be necessary.  A plant can go from seedling to seed-bearing within as little as a month, and once the plant produces seed, the seed bank can last for years.  Field crews must find and apply a few drops of herbicide to every single root in order to kill the plant, no small task when the plant has covered several kiawe trees.

On the islands of O`ahu and Hawai’i, ivy gourd is invading natural areas. On Guam and Saipan, ivy gourd is so established that the only way to limit it may be through biocontrol.  Insect pests have been released in these areas.   On Maui, control efforts have reduced ivy gourd to a level that would no longer support a viable biocontrol population.  The only way to eradicate it is to get rid of the remaining plants, monitor locations for new plants, and prevent new introductions.

If a plant nursery is infested with ivy gourd, it’s almost inevitable that seeds and plant material will be spread in contaminated soil.  This may help explain why we find ivy gourd in golf courses.  A huge infestation was discovered on Lāna‘i in 2006, and with continued effort the population is being knocked back.

And those open spaces on Maui?  Above the development of Lahaina and Kīhei are the remnants of the native dryland forest ecosystem. The leeward slopes of Haleakalā, where this ecosystem was once predominant, still harbor stands of native trees.  This is where ‘iliahi (sandelwood) grows.  The wiliwili tree can be found here, as well as the naio trees that gave us the name for the area: Kanaio.  These areas have been greatly altered by ranching and the introduction of goats and deer, yet they still include rare native plants and insects.  There is no ivy gourd here.  Ivy gourd would thrive here if introduced into these native forests.  Ivy gourd would smother the existing vegetation, leaving curtains of green where there once were diverse and rare ecosystems.

Help us protect these rare ecosystems on by finding and reporting ivy gourd in Maui’s residential and rural areas.  Do not grow ivy gourd.  If you suspect you may have ivy gourd on your property, please call the Maui Invasive Species Committee at 573-MISC (6472) and we will remove it, free of charge.

The Big Drip: Possible Water and Soil Impacts of the Miconia Invasion in Hawai‘i

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By Thomas Giambelluca

Miconia leaf with water dropletsAnecdotal evidence suggests that, besides impacting biodiversity, the invasive tree Miconia calvescens is causing landslides and other soil erosion problems in Tahiti, where it has displaced native forest. As miconia takes hold in Hawai‘i, local scientists and environmental organizations have voiced concerns about its potential hydrological impacts: increased flooding, diminished groundwater supply, loss of topsoil, and siltation of coral reefs.

Miconia invasions lead to dense, monotypic stands with little or no ground-covering vegetation. Miconia’s large, dark leaves reduce light levels beneath the canopy, thereby inhibiting the germination and growth of other plant species. Large leaves also produce relatively large throughfall drops during and after rain events.

“Throughfall” refers to rainwater that reaches the forest floor. Some throughfall consists of raindrops that fall through the forest canopy without hitting any leaves or branches. The rest comes from drops that splash or drip from wetted vegetation. Water that drips from the leaves of tree canopies can be much larger than raindrops. If falling from a great enough height, these large drops can reach kinetic energy levels that exceed that of natural rainfall in open areas. Because these large drops hit the ground with greater force, they can result in greater impacts to the soil.

The soil surface, exposed due to the lack of ground cover, is vulnerable to higher rates of “detachment,” the breakup of clumps of soil into small particles. Mobilized by large, high-energy throughfall drops, these particles can clog soil pores and reduce rates of infiltration. This leads to overland flow during rainfall events, a process unlikely to occur on undisturbed soils of native forests on Pacific Islands.

In a pilot study funded by the U.S. Fish and Wildlife Service we were able to verify that light levels under miconia stands in Onomea on Hawai‘i Island are very low.* Based on a limited survey, we also observed ground cover to be very sparse under miconia, with very little live vegetation and meager leaf litter. Most studies have shown that runoff and soil erosion become severe as ground cover declines below fifty percent, as was the case for the Onomea miconia stands.

Using laser disdrometers, Japanese researcher Dr. Kazuki Nanko helped us measure the size and velocity of throughfall drops under miconia and other tree canopies at Onomea and nearby field sites. Dr. Nanko found that miconiaproduced throughfall drops up to seven millimeters in diameter, much larger than typical two-millimeter diameter rainfall drops and significantly larger than throughfall drops under native trees.

Large miconia leaves act as umbrellas, shading out sunlight

Large miconia leaves act as umbrellas, shading out sunlight

The next step in this research is to observe runoff and erosion processes at miconia plots and control sites. Due in part to the effectiveness of miconiaeradication efforts in Hawai‘i, we have not been able to find stands large enough and in proximity to appropriate control sites to do the research in Hawai‘i. It is therefore likely that further study of hydrological impacts of miconia will be based in French Polynesia, where the miconia invasion is much more advanced.

Thus far, our studies indicate that in areas invaded by miconia, the effects of sparse ground cover, high-impact throughfall, and overland flow could combine to produce excessively high rates of soil erosion. Accelerated soil erosion removes topsoil, depriving native plants of access to nutrients and water and leading to siltation of streams and the near-shore marine environment.

Thomas Giambelluca is a professor at the University of Hawai‘i at Mānoa, where he has been conducting research on the climate and hydrology of Hawai‘i and other tropical areas for nearly 30 years.

*Dr. Ross Sutherland, professor and chair of the Geography Department at the University of Hawai‘i (UHM); Ryan Mudd, UHM graduate assistant; and Dr. Alan Ziegler, Singapore National University, contributed to this study.

Originally published in the Summer 2010 edition of the Maui Invasive Species Committee’s newsletter Kia‘i i Nā Moku o Maui Nui. The full newsletter is posted at hear.org/misc/newsletter/

Creative solutions for controlling the little fire ant

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Check out the video below to see Dr. Cas Vanderwoude and the “Spackler of Death,” a creative solution to solve the problem of getting ant bait into trees to control the little fire ant or Wasmannia auropunctata. Learn more about the little fire in Hawai‘i and the Pacific at lfa-hawaii.org and littlefireants.com.

Poisonous Rubber Vine Needs to be Controlled

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Rubber vine flower and plant

The rubber vine may appear to be a beautiful plant but it is actually poisonous. The vines will also creep up trees and into their canopies and foul up streams. (Photo by MISC)

When the crew from the Maui Invasive Species Committee (MISC) arrived on Moloka‘i in February of 2005, they soon realized this was not going to be just another week at work. They were assisting the Moloka‘i/Maui Invasive Species Committee (MoMISC) in controlling a large infestation of rubber vine plaguing the Kamalō and ‘Ualapu‘e areas. The pest had invaded over five acres, forming impenetrable thickets that made it difficult to control. Just looking at the vast amount of area conquered by this one invasive plant made the MISC crew realize why the two-person MoMISC team called in reinforcements.

Controlling the large population was a daunting task and, at first, overwhelming.  But one by one, vine by vine, the crew attacked the rubber vine as if they themselves were an invasive species, quickly devouring everything in their path. By the end of the week, the once dark forest of rubber vine blanketing the treetops was transformed into a more open area with sunlight. By helping to initially suppress the pest, MISC was making it manageable for MoMISC to monitor and treat it in the future.

Here on Maui, we are fortunate that we do not have such large rubber vine populations.  Instead, we have limited infestations growing in residential areas. There is hope that we can eradicate this invader before it affects our natural and agricultural areas as well as quality of life.

Rubber vine (Cryptostegia grandiflora on Maui, C. madagascariensis on Moloka‘i) are vigorous climbing vines from Madagascar that can scramble their way 30 meters up a tall tree or grow as an unorganized shrub-like clump of vines one to two meters tall.  The plant invades waterways forming dense, impenetrable thickets that smother riparian vegetation and decrease biodiversity. Rubber vine can also impact ranching operations by restricting livestock access and lowering pasture productivity.

This invasive plant is extremely poisonous; it contains cardiac glycosides, chemicals that interfere with heart function in humans and animals when the plant is ingested. Contact with the plant’s milky sap can cause burning rashes and blisters. When the vine is dry, a powdery dust emerges that can cause violent coughing, swelling of the nose, and painful blistering of the eyelids.

Rubber vine has large, showy pinkish-purple flowers with five petals arranged like a funnel. Its shiny, dark green leaves, directly opposite each other, range from two to four inches long. The distinctive triangular seed pods average three to four inches in length and grow in wing-like pairs. Approximately 200 days after formation, the seed pods dry out and split open. Seeds with silky hairs are released into the wind and waterways.  Approximately 95% are viable – increasing the potential for rubber vine to rapidly spread.

In addition to natural dispersal, rubber vine can be introduced to an area by animals or humans. Livestock can carry seeds long distances through agricultural fields. Contaminated vehicles and machinery transport seeds from one worksite to another. Cultivation of rubber vine as an ornamental plant makes the problem much worse, especially since a plant may live for up to 80 years. Rubber vine is widely available to the public through Internet seed companies, few of which describe the plant’s noxious qualities.

In order to prevent the spread of rubber vine, areas downstream and downwind from known infestations must be inspected. Do not import, purchase, or plant this toxic species in your yard. If you have rubber vine on your property, call MISC and give permission to control it. If you see rubber vine growing or for sale, call MISC at 573-MISC. Encourage friends and family not to buy this or other pest plants so nurseries will stop selling them.

We are happy to report that since MISC assisted MoMISC in February 2005, the five-acre rubber vine population has been significantly reduced and eradication of this pest is within reach for the Friendly Isle. Inclusion of rubber vine on the Hawai‘i State Noxious Weed List is currently under consideration. Until it is listed, it is up to residents and visitors to protect Maui from this aggressive pest so that we can avoid dealing with large populations such as that once found on Moloka‘i.

By Joylnn Paman
Originally published in the Maui News, January 13, 2008 as part of the Kia‘i Moku Column. Check out all of the MISC articles in the Kia`i Moku series at: www.hear.org/misc/mauinews/

Pampas Grass: All Species on Maui are Invasive

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Pampas grass plumes were once so popular they even decorated parade floats

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 19th 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.

stand of Cortaderia jubata plant, or pampas grass

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/

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Contact Us

Maui Invasive Species Committee (MISC)
Office: (808) 573-6472
Press and Media Inquiries: (808) 344-2756
Mailing Address:
PO Box 983, Makawao, HI 96768

Acting Manager / Public Relations: Lissa Strohecker
E-mail: miscpr@hawaii.edu

Special Projects: Teya Penniman
E-mail: miscmgr@hawaii.edu

Statewide Pest Hotline: 808-643-PEST
Report a Pest Online