Invasive Plants — Page 4 — Maui Invasive Species Committee (MISC)

Poisonous Rubber Vine Needs to be Controlled

Posted on December 8, 2011 by Lissa Strohecker Leave a Comment

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/

Plans in the Pipeline to Protect ‘Ōhi‘a From ‘Rust’

Posted on December 1, 2011 by Lissa Strohecker Leave a Comment

Puccinia psidii or “ohia rust” is found on the leaves of an ohia tree. Rob Anderson photo

It starts with a spot, a tiny dot of orange on a leaf bound for Hawai‘i. It could be on cut foliage destined for a florist or on a tree fated for a Hawai‘i yard. The miniscule speck of orange grows, produces spores, and covers the plant. Hawai‘i’s moist climate creates the perfect habitat for the little orange organism, a type of fungus known as a rust that attacks plants—often fatally. The trade winds spread the rust spores to more hosts and within months trees across Hawai‘i have turned brown, lost their leaves, and begun to die.

If a new strain of this fungus rust arrives in Hawaii it could devastate ohia forests. Orange rust fungus covers the leaves of a rose apple tree. FOREST & KIM STARR photo

In 2005 the rust attacked an invasive tree in the myrtle family–rose apple, but the rust grows on many myrtaceae species, including ‘ōhi‘a. The Hawai‘i Department of Agriculture identified the rust as Puccinia psidii and named it “‘ōhi‘a rust” in recognition of its impact on ‘ōhi‘a. If a new strain of the rust arrives there is a very real chance that it will attack ‘ōhi‘a and cause the same level of damage as it did to rose apple. This could be devastating: ‘ōhi‘a makes up 80% of our native rainforest and is the keystone species in the watershed. In an effort to protect ‘ōhi‘a and our rainforest–the source of our water–the Hawai‘i Department of Agriculture is proposing a ban on the import of plants that could carry a new variety of the rust.

In 2008 HDOA implemented an interim rule, a temporary ban on the import of ‘ōhi‘a, but it was only active for one year. This new rule will protect ‘ōhi‘a as well as other, commercially important myrtle species, such as eucalyptus and ornamental trees.

‘Ōhi‘a covers nearly 1,000,000 acres in Hawai‘i, provides food for ‘i‘iwi, ‘apapane, ‘ākohekohe, and other rare birds; shelter for their nests; and habitat for native insects, snails, and other species.

Like a flu or a cold, there are different strains of rust. The strain of ‘ōhi‘a rust currently in Hawai‘i does kill ‘ōhi‘a seedlings, but very few. However, the impact could be much higher. To evaluate the rust’s threat, Hawaiian ‘ōhi‘a seedlings were grown in Brazil, the home range of the fungus. Researchers exposed the seedlings to various strains of the rust, some which proved deadly. These tests showed that a new rust strain is a potent threat to the Hawaiian forests and watersheds.

The ban will stop the import of plants and foliage of myrtle family that hitchhike into Hawai‘i from out-of-state or international sources. This material is commonly used in flower arrangements, but after the interim ban, many florists quit using eucalyptus as cut greens in flower arrangements. Local sources of eucalyptus can still be used, and in doing so, local jobs are protected along with ‘ōhi‘a. If growers want to import a myrtle species into Hawai‘i, they can do so after obtaining a permit and agreeing to quarantine the plant for one year.

Before the ban goes into effect HDOA will hold public hearings throughout the state. Buy local–support florists who use locally grown flowers and foliage, or use locally grown flowers and foliage yourself. By making this choice you are helping to protect ‘ōhi‘a and our forests. Visit www.hear.org/species/puccinia_psidii/ to learn more.

Article by Lissa Fox Strohecker

Originally published in the Maui News, October 9th, 2011 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!

Biocontrol precision is weapon against invaders

Posted on September 6, 2011 by Lissa Strohecker Leave a Comment

Lloyd Loope

Last month I began to present my point of view as a conservation scientist relevant to current “controversy” over biocontrol of strawberry guava (Psidium cattleianum), Hawaii’s most damaging invasive plant species. I touched upon the generally accepted theory that many highly invasive plant species, held in check by insects and pathogens in their home range, become unbeatable competitors in their introduced range where those insects and pathogens are lacking. Strawberry guava exemplifies the “enemy release” theory; it is attacked by virtually no insects or pathogens wherever it invades on many tropical islands of the world.

Though I’ve always supported the concept of biocontrol as a potential tool for Hawaii’s most widespread and most invasive plants, I recall a personal pessimism in the 1980s that biocontrol success might be unlikely in this case because guava is in the myrtle family (same as Hawaii’s ‘ōhi‘a) and commercially important common guava (Psidium guajava) is such a closely related sister species.

A strawberry guava tree in Curtiba, Brazil is heavily infested with the galls of the scale insect Tectococcus ovatus. This is the typical effect of the insect on the plant. It was a result of a naturally developing infestation of the insect in the plant’s native range. U.S. Forest Service photo

But state and federal natural resource agencies in Hawaii have managed to cobble together a remarkably stellar program to address the rampant invader. In 1991, the National Park Service and the University of Hawaii began to collaborate with the Federal University in Curitiba, Brazil, to identify and evaluate potential biocontrol agents. After 10 years of field observations and other testing working within the native ranges of both strawberry guava and common guava in Brazil researchers found 133 insect species in 12 orders and 80 families that fed on strawberry guava. Thirty-one of those species fed only on plants in the myrtle family, and five species fed only on strawberry guava and not at all on common guava. The collaborative program zeroed in on Tectococcus ovatus, a scale insect that feeds on the new growth, creating galls on the leaves of strawberry guava. This scale insect was the choice for more intensive work based on the relative severity of damage inflicted on P. cattleianum and the ease of handling it.

Tectococcus ovatus was brought to containment facilities in Hawaii and Florida, where strawberry guava is also invasive, for intensive experimental testing to ensure its safety as a biocontrol agent. Many related native and non-native plants were tested as potential host species. Strawberry guava is the only plant in Hawaii that this insect is able to feed on. Dr. Tracy Johnson of the U.S. Forest Service in Hilo has brought the program close to fruition over the past eight years.

The insect reduces the plant’s energy and nutrients available for growth and reproduction. Heavy infestation is expected to accelerate leaf drop and reduce fruit and seed production. Some fruit will be produced and the plants are not expected to die. If the scale insect thrives, it will level the playing field between the invasive strawberry guava and native forest species.

What other species in the ecosystem will be affected by the expected decline in strawberry guava fruit production? Feral pigs and a few species of non-native birds will lose a seasonal carbohydrate diet supplement during the September-December fruiting season. These same species are fully able to thrive in areas where there is no strawberry guava.

Hawaii is confronted by intractable invasive species problems, but by integrating prevention, early detection, rapid response, and biocontrol we can begin to address these problems. Biocontrol is an essential part of invasive plant management strategies in New Zealand, Australia, and the U.S. mainland. Florida has become a leader in biocontrol in the past decade. For example I recently learned that thanks to two insects introduced about 10 years ago as classical biocontrol agents, the notorious Melaleuca, or paper bark tree is no longer invasive in the Florida Everglades! My scientific opinion is that biodiversity conservation in Hawaii will not succeed without the enlightened use of biological control.

Lloyd Loope is a research scientist with the U.S. Geological Survey stationed at the Haleakala Field Station. He holds a doctorate in botany from Duke University and is an active Maui Invasive Species Committee member.

Originally published in the Maui News, October 12, 2008 as part of the Kia‘i Moku Column.
You can see all the articles in the Kia‘i Moku series http://www.hear.org/misc/mauinews/

Strawberry guava sows seeds of infestation

Posted on August 30, 2011 by Lissa Strohecker 1 Comment

The fruit if strawberry guava are eaten by birds that spread the tiny seeds. Photo by Forest & Kim Starr

When I came to Maui 28 years ago to work as a research biologist at Haleakala National Park, one of the first things I learned was that strawberry guava (Psidium cattleianum) was regarded as the most damaging invasive plant in the state. A year later, I was in Kipahulu Valley and experiencing the amazing guava fruiting and dispersal season. The 10-30 foot tall trees left a sea of red fruits that still lurks in my memory. There were dense, extensive guava thickets of tens of acres at the 2,000-3,000 ft elevation level in the valley. One could scarcely walk through; there were literally no other species present. These devastated areas contrasted sharply with the rich biodiversity in nearby areas with intact native understory vegetation.

A dense infestation of strawberry guava, or waiawī , in the Makawao Forest Reserve. Photo by Forest and Kim Starr

At that time, C.H. Diong, a graduate student at UH-Manoa, was putting the final touches on his Ph.D. thesis. Diong showed that feral pigs had been the primary agent spreading strawberry guava from the mouth of the valley upslope for the past 30 years or so. The pigs fed almost exclusively on guava fruits during September-December. The seeds pass through the pigs’ digestive tracts with no loss of viability. Fruiting was occurring only below about 3000 ft elevation but the seeds could germinate and grow much higher, up to over 4000 ft in the valley.

Years later, my colleague Dr. Art Medeiros did his Ph.D. thesis on the biology of weeds in Kipahulu Valley and East Maui. Art estimated that strawberry guava already occupies over one-third, or 8900 acres, of its potential area of dominance on East Maui. Although feral pigs had been eliminated and fenced from Kipahulu Valley since the late1980s, Art found that non-native birds, primarily the red-billed leiothrix, were also spreading strawberry guava seeds. Strawberry guava plants were still not fruiting above 3000 ft, but seeds planted experimentally (or those carried by birds or pigs) germinate at much higher elevations. Strawberry guava now reaches as high as 5300 ft on East Maui in at least one location.

Strawberry guava has infested the outlined area on Mahana Ridge, just to the east of Honokahua Valley in West Maui. Photo by Randy Bartlett.

Newly established guava plants can spread vegetatively by root sprouts. On all the major islands, nearly monotypic guava stands infest thousands of acres of moderately wet (mesic) and very wet forest. Strawberry guava is considered a serious threat to native forests due to its ability to invade relatively undisturbed areas and form thickets with dense mats of feeder roots. Dense invasion allows only about 5% of sunlight into the understory. The guava at first invades under native canopy, then expands and closes the mid-level canopy position, preventing the establishment and regeneration of all other species, including the dominant native forest plants – ohia and koa. Although it continues to expand into relatively pristine native forest areas, strawberry guava is now so widespread in Hawaii that its future impacts are expected to consist mainly of filling in areas creating monotypic stands.

As one of the founding members of the Maui Invasive Species Committee, I never considered taking on strawberry guava as a MISC target given its wide distribution and abundance and MISC’s limited resources. We always hoped for the eventual possibility of identifying an effective biological control.

A generally accepted theory of biological invasions is that certain plant species, held in check by insects and pathogens in their home range, become invasive in their introduced range where those insects and pathogens are lacking. Strawberry guava seems to fit the “enemy release” theory perfectly. In Hawaii, it is currently attacked by no insects or pathogens.

The first biocontrol researcher for this species, Dr. Charles Hodges, traveled to coastal Brazil in 1988 and reported that strawberry guava occurs not in dense stands but as scattered trees and rarely in small clumps. He noted that “few trees were observed that had not been attacked by at least one kind of insect,” and “often four or five types of insect damage could be identified on the same tree.” After 20 years of research to determine the best potential biocontrol agent, the scale insect Tectococcus ovatus has jumped through all the hoops but one – public opinion.

Lloyd Loope is a research scientist with the U.S. Geological Survey stationed at the Haleakala Field Station. He holds a doctorate in botany from Duke University and is an active member of the Maui Invasive Species Committee.

Originally published in the Maui News, September 14, 2008 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/

Mullein came to fight erosion, exists as threat to silversword, other plants

Posted on August 8, 2011 by Lissa Strohecker Leave a Comment

By Joylnn Paman

Originally published in the Maui News, September 10, 2006 as part of the Kia‘i Moku Column.

The slopes of Haleakalā are the only home for some of the rarest plants and animals in the world. Among them, `āhinahina, the Haleakalā silversword grows for up to 50 years before flowering and casting its seeds for the next generation to the wind. To protect these and other native species the Maui Invasive Species Committee (MISC) partners, including Haleakalā National Park, are on the lookout for invasive plants and animals that could threaten this delicate environment.

Common mullein (Verbascum thapsus) is one such invader. It was first introduced to the Island of Hawai`i for erosion control in the early 1900’s and has since become well established on Big Island volcanic slopes. Scientists have observed that mullein out-competes other plants and grows to an abnormally large size, particularly at higher elevations on Hawai`i. This has raised concern that mullein would quickly invade and out-compete native plants in the higher elevation habitats on Haleakalā.

This Eurasian plant has become a widely established weed throughout temperate areas of the world. Its gray-green, felt-like leaves range from 4-12 inches long and 1-5 inches wide. Mullein grows in a low rosette for the first year or two and at maturity sprouts up an erect stalk with yellow flowers. This pest grows up to 10 feet tall and can invade elevations from sea level to above 10,000 feet.

Several characteristics make mullein all too successful as an invasive plant. Although noted for the ability to quickly colonize disturbed areas, it does not require disturbance to rapidly invade the loose volcanic cinders and `a`ā lava in Hawai`i. This weed grows in dense thickets displacing slower growing and longer maturing native species, such as the silversword. Like the silversword, protective hairs on the leaves of mullein reflect the intense alpine sunlight, pre-adapting this weed for the arid conditions on Haleakalā.

Unlike the silversword, mullein produces large quantities of seed, which remain viable for long periods of time. Each mature mullein plant sprouts a flowering stalk, which develops up to 150,000 seeds. Seeds may remain dormant for over 100 years, waiting for favorable environmental conditions or dispersal into suitable habitats. With silverswords taking up to 50 years to seed compared to just two or three years for mullein, it is easy to imagine how mullein might displace `āhinahina. Because of these invasive characteristics and the high risk to native species, mullein was declared a Hawai`i State Noxious Weed in 1992. In the late 1980’s, two immature mullein plants were found in Haleakalā National Park along the roadside leading up to the summit and were immediately destroyed. None have been found in the park since. Soon after that first incident, it was discovered that an upcountry nursery raised mullein and sold it to a number of homes. When informed by park staff of the ecological threat, the nursery agreed to halt sales and destroy the remaining stock. This cooperation sparked an article in The Maui News urging mullein purchasers to destroy their plants.

It is difficult to know if everyone destroyed their plants and there’s always the possibility that there are new locations. Just this summer, a new site was discovered Upcountry. MISC was notified and responded immediately. The plant was killed and the seeds were collected. The cooperative landowner is now monitoring the property for additional plants that may sprout in the future.

Today, early detection of mullein is critical to keeping Maui Nui free of this pest. Do your part to stop the spread of this and other invasive species. Do not purchase, sell or import unknown plants. Learn how to identify mullein and report possible locations to the Maui Invasive Species Committee at 573-6472.

Check out all of the MISC articles in the Kia`i Moku series at: www.hear.org/misc/mauinews/

All hands can be part of defense against Miconia invasion

Posted on August 5, 2011 by Lissa Strohecker Leave a Comment

: Makawao residents point to where a miconia seedling grew out of their hapu`u fern in Makawao

: Large miconia leaves act as umbrellas, shading out sunlight

In April of 2006, a Makawao resident noticed an unusual plant growing in his yard. It had large leaves with purple undersides. Curious, he did some research and discovered it was miconia – a plant native to Central and South America that is invading Maui’s rain forests. Surprised by his findings, he immediately called the Maui Invasive Species Committee (MISC). MISC staff investigated and was stunned to find a miconia seedling growing out of a hāpu‘u fern in Makawao! To date, miconia was known only from East Maui (one intentional planting in West Maui had been eradicated). Because the resident knew the origin of the hāpu‘u (Big Island), MISC surmised that a tiny miconia seed had hitched a ride on a hāpu‘u harvested from a miconia-infested area and sprouted three years later. The miconia plant was young and had not seeded, a plus for the environment. Left undetected, the plant would have quickly matured, eventually releasing ten to twenty million seeds each year into an area thought to be miconia-free.

Miconia was first introduced to Maui in the 1960’s as an ornamental plant in Hāna, then quickly spread to the surrounding forests. By 1993, one plant had multiplied into thousands, distributed over a 2,000-acre area. Alarmed by miconia’s potential to overwhelm available resources, conservation agencies pulled together and formed the Maui Invasive Species Committee (MISC), a voluntary partnership to protect Maui County from invasive plants and animals. Over the years, MISC’s focus broadened to include many other invasive species, but miconia continues to be the top priority plant target. MISC now has a full-time crew searching for and destroying miconia over thousands of acres in East Maui.

Miconia leaves can grow to be the size of a small child, averaging 2-3 ft long and 1 ft wide. The leaf has a dark purple underside, oval shape, and 3 distinct veins. In its native environment of South and Central America, miconia’s large leaves help the plant capture limited sunlight in dense, dark forests. On Maui, the forest structure has a more open canopy, so many native plants have not developed a tolerance for dense shade. Miconia’s leaves act as “light” umbrellas, casting a deep and often deadly shade over native vegetation.

A characteristic common to many invasive plants is the ability to produce large quantities of seeds that remain dormant for a long time. Miconia is no exception. Each mature plant can produce millions of seeds per year, which may not germinate for another 8–10 years. The rapid spread of miconia in East Maui has been aided by unintentional movement of these tiny seeds, as small as a grain of sand. Birds, hunters, hikers, vehicles, and even the movement of other plants, can bring miconia to new areas.

You can help combat the spread of miconia. Learn how to identify the plant. A good resource for photos and information is www.mauiisc.org. Always clean your shoes and gear before and after hiking. Know the origin of plants that you purchase. If you think you have found miconia, report the location to 573-MISC (6472). If you have miconia on your property, allow MISC to control it free of charge. Just by doing these simple preventive measures, you are helping to keep Maui nō ka ‘oi. Keep an eye out for this new monthly column to learn how you can protect Maui from invasive plants and animals that are threatening Maui County.

By Joylnn Paman
Originally published in the Maui News, August 13, 2006 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/

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