Invasive Species of the Pacific Northwest

Flowering Rush, Butomus umbellatus, Grassy Rush, Water Gladiolus

Lilia Bannister

FISH 423 // Olden

Autumn 2014

Figure 1. Top: Flowering Rush, Butomus umbellatus, growing in a water garden (photo credit: Bennetts

Water Gardens); Bottom: Flowering rush overtaking an irrigation stream (photo credit: Natural

Resources Conservation Service, Montana, United States Department of Agriculture).

Classification

Order: Alismatales Family: Butomaceae Genus: Butomus Species: Butomus umbellatus Common names: Flowering Rush, Grassy Rush, Water Gladiolus

Identification Key

As a perennial Eurasian aquatic plant that exhibits characteristics from both the Cyperaceae and Juncaceae families (Jacobs 2011), Butomus umbellatus is unique and identified as the only species of the Bitomaceae family. Although it is the sole species of this family, it remains a distinguished species in the Angiosperm and monocot groups. Monocots have parallel veins, flowers in 3 parts, a larger root system, and one cotyledon (Stevens 2012), all of which B. umbellatus can identify. It is generally found along the shoreline in the littoral zone of rivers and slow moving bodies of freshwater (Jacobs et al. 2011). B. umbellatus is commonly referred to as flowering rush or grassy rush and is known to grow in waters up to 20 feet (6 meters) deep. The stems are green and triangular in cross section (Figure 3), generally grow up to five feet (1.5 meters) tall, and are grounded by an extensive system of fibrous rhizomes (Oregon Department of Agriculture 2014). Depending on the depth of where the plant is located, it will either emerge and flower or remain submerged. If the plant is growing in shallower waters, it will grow above the surface and produce radially symmetric 1-inch light pink flowers in an umbrella-shaped formation (Figures 1, 2). Each flower consists of six petals, six pistils, and nine stamens arranged in two whorls (Jacobs et al. 2011), which blossom between June and August (Montana Weed

Control Association 2009). These flowers will either grow fruit that open at maturity and disperse seeds, or they will remain sterile and reproduce through rhizomes and bulblets (Oregon Department of Agriculture 2014). These reproductive differences can also be assessed through their genes: diploid cells (2n = 2x = 26) produce a seeding plant and triploid cells (2n = 3x = 36) produce a sterile plant (Department of Ecology of Washington State 2008). Seeds are adapted to float so they can be carried along with the flow of the water (Center for Invasive Species and Ecosystem Health 2010).

B. umbellatus is predominantly and most easily identified by its flowers, but when the plant is rooted in deeper waters it remains underwater and will therefore not produce any buds or flowers, making identification much more difficult. When submerged, the plant grows narrow and limp triangular leaves that can reach up to about 3 feet (1 meter) long (Center for Invasive Species and Ecosystem Health 2010). This is opposed to the stiffer and more supported leaves of the variety that grows above the surface, since those leaves can twist and spiral toward the top of the

Figure 2. Petal, stamen and pistil arrangement

of B. umbellatus (photo credit: Christian

Fischer, Cofrin Center for Biodiversity,

University of Wisconsin-Green Bay).

plant (Jacobs et al. 2011). Both types, the underwater variation specifically, can also be identified by the bulblets that form on the roots. These bulblets are the primary form of reproduction for the submerged and sterile plants, and when the rhizomes are disturbed the buds are able to break off and produce new plants (Jensen 2009).

Life History

Life Cycle

The life cycle of B. umbellatus parallels that of any monocot in that it begins as a seedling, grows and develops stems, leaves, and roots, and matures into a flowering plant. From there, the flowers produce seeds, which germinate once dispersed and become seedlings again (US Fish & Wildlife Service 2008).

Feeding Habits

Vascular plants such as flowering rush feed through their root system and shoot system. The fibrous roots collect nutrients from intake from the soil and the shoot system uses its leaves to capture the suns light and extract nutrients from

photosynthetic processes (US Fish & Wildlife Service 2008).

Reproductive Strategies

As a perennial, the life cycle of B. umbellatus can last for many years, and although it produces fewer seeds compared to other types of flowering plants, their seeds are more likely to be environmentally fit and successful in reproduction (US Fish & Wildlife Service 2008). The three main strategies of reproduction of B. umbellatus are sexual reproduction through seed production and dispersal, asexual reproduction through clonal means of bulblet production, and asexual reproduction through vegetative reproduction processes (Lui et al. 2005). When the inflorences of the plants blossom (Figure 1, Top), they can contain up to about 50 flowers each (Lui et al. 2005). If the plant is fertile, these flowers each produce a fruit containing seeds (Figure 4). When the flowers have reached their sexual maturity, the fruit opens and releases the seeds into the environment (Oregon Department of Agriculture 2014). Seeds increase the distance of dispersal and establishment due to their adaptation to float on the water’s surface (Center for Invasive Species and Ecosystem Health 2010). If the water is moving via a light current, the seeds can be carried greater distances, which can lead to more widespread invasions. In a case study of B. umbellatus, it was also found that each flower is protandrous, therefore reducing the risk of self-pollination (Bhardwaj and Eckert 2001) and increasing successful reproduction rates through seed production. Vegetative reproduction is another significant form of reproduction of B. umbellatus. Vegetative reproduction occurs when a plant regrows from something that has been separated from the original plant, in this case, fragments of the rhizomes or bulblets. (US Fish & Wildlife Service 2008).

Figure 3. Triangular cross section of B.

umbellatus stems (photo credit: Gary

Fewless, University of Wisconsin,

Green Bay, Wisconsin).

Clonal reproduction follows the production of bulblets, small bulbs-like structures attached to the rhizome (Figure 5) that are broken off by anthropogenic disturbances in the substrate or water above (Rice 2008). Bulblets are a very important means of reproduction to the triploid sterile plants that do not produce flowers or seeds (Lui et al. 2005). Each bulblet is loosely attached to the rhizome. Once broken off, the bulblets themselves sprout and can establish a brand new plant. This allows new plants to grow easily and often because of frequent disturbances in the environment (Jacobs et al. 2011). The advantages of these two methods of asexual reproduction are the benefits of quick and immediate dispersal. Adjacent plants can be established quickly and easily since bulblets and rhizomes are already rooted in the substrate, and populations can grow rapidly without the waiting time for flowers to blossom and fruits to mature. The disadvantage however, is the absence of reproductive variation since no genes are being exchanged between individual plants. This can reduce fitness if the plants are facing changes in the ecosystem that require adaptation. With methods of sexual reproduction, the plant is able to account for these changes and can adapt to better suit the environment. Disadvantages of sexual reproduction would include the complications of pollination dependency and the chances of unsuccessful seed establishment.

Environmental Tolerances

B. umbellatus is an indigenous plant to Europe and Asia that thrives in areas of slow-moving or relatively stagnant water (Core 1941). It is known to be tolerant to a great temperature range and therefore has a higher probability of establishing in differing climates (Center for Invasive Species and Ecosystem Health 2010). It is most commonly found in shallower waters and especially areas with fluctuating water levels such as wetlands, irrigation ditches, and the shores of lakes. These shallow areas of near-standing water are more prone to the successful growth of rhizomes and bulblets because when the water levels lower or when they completely dissipate, the sun warms the ground. Since warmer temperatures enhance advantageous growth and sprouting conditions of the bulblets, once they are grounded well in the muddy substrate they can sprout more quickly and the population can spread (Hroudova 1996). Historically and in other regions of the world, specifically Eurasia, the expansion of flowering rush has been stifled by native species such as reeds. Interactions with native flora in the United States however are not yet known (Jacobs et al. 2011).

Figure 4. B. umbellatus seed detail (photo

credit: Bargeron 2008).

Figure 5. B. umbellatus rhizome detail

(photo credit: Bargeron 2008).

Biotic Associations

The parasite physoderma butomi Schroeter was discovered on leaves of B. umbellatus in 1883 in Lake Michigan (Sparrow 1974). The resting spores generally infect the plant on the subepidermal level of the leaves rather than the epidermis layer itself, and were also noted to infect the stalks of inflorescences. From a flat colony of the fungus, a zoospore will develop and germinate. When this occurs, the zoospore bursts and is

released into the water in which it attaches to seedlings and beings to invade, continuing the infectious cycle (Sparrow 1974). No further critical research has been done on parasites or pathogens of B. umbellatus, but it has been noted that aquatic environments containing flowering rush support great pond snail populations. These snails host a parasite that has been identified as a cause of ‘swimmer’s itch’ (Jacobs et al. 2011).

Current Geographic Distribution

Although widespread throughout Asia and Europe, B. umbellatus has generally only been reported in the northern part of the United States. It has been documented in Washington, Idaho, Montana, North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Iowa, Wisconsin, Illinois, Michigan, Indiana, Ohio, Pennsylvania, New York, Vermont, New Hampshire, Maine, Massachusetts, and Connecticut (Figure 6). In Washington State, it has been reported at these various sites and in these counties: Columbia River (Tricities) (Benton), Long (Spokane), Nine Mile (Spokane), Pend Oreille R (Pend Orielle), Shaver (Pierce), Silver (Whatcom), Yakima River (Benton), and Yakima River (Prosser) (Benton) (Figure 7).

Figure 6. Documented Cases in United States (photo credit: EDDMapS, University of Georgia - Center

for Invasive Species and Ecosystem Health).

History of Invasion

The first recorded evidence of B. umbellatus in North America was in 1897 in Canada along the St. Lawrence River. In the United States, it was first observed in the early 1900s and an early case of establishment in Lake Champlain, New York was published in 1929 (Brown and Eckert 2005). Over the next decade it was seen to be spreading throughout Vermont, Ohio, Michigan, and even West Virginia.

In the Northwest, its introduction is believed to be from the invasion in Peaceful Bay, Flathead Lake, Montana, in 1964. From there it was carried along the Flathead River and Clark Fork River to Lake Pend Oreille in Idaho. The Pend Oreille River then continued to carry it into Washington State in the late 1990s, and today concern is

growing about its spread toward the shores

of the Columbia River (Department of Ecology of Washington State 2008, Jacobs 2011).

Invasion Processes

Pathways, Vectors and Routes of Introduction

Following B. umbellatus’ initial introduction into North America, further invasions have been thought to occur from multiple pathways. Some believe populations were introduced by the horticulture trade for the ornamental attraction of flowering rush as a water-

garden plant (Indiana Department of Natural Resources 2013). Some think nurseries are to blame for the Great Lakes invasions because of imported seeds, and the invasion of other regions due to the possible introduction of the plant as a food source for waterfowl (Core 1941, Department of Ecology of Washington State 2008). Studies show that the diploid plants originated from Europe and Asia and that the triploid plants originated from the Netherlands and Northern Germany (Department of Ecology of Washington State 2008). Regardless of the reason of introduction, all are the effects of pathways of human involvement.

Factors Influencing Establishment and Spread

The biggest factor concerning the spread of B. umbellatus is its varying methods of reproduction. The vegetative reproduction strategies of this plant prove to make spread very easy and constant when rhizome systems are disrupted, which can be often depending on the ecosystem it is established (US Fish & Wildlife Service 2008).

As mentioned before, vegetative reproduction occurs when a portion of the original plant is broken off or separated and a new plant is able to grow from the fragment that has been removed. This, paired with annual production of seeds in diploid plants, can create a high-impact cycle of the spread of flowering rush. An interesting observation to note is that the geographic distribution varies between the fertile and sterile B. umbellats populations, leading to the need for different management and eradication

Figure 7. Locations of WA Department of

Ecology survey sites. B. umbellatus was found at

8 sites (black marks) out of the 534 surveyed (red

and yellow marks) (photo credit: Department of

Ecology of Washington State).

approaches (Department of Ecology of Washington State 2008). In North America, the plants identified in the northwest have been found to consist of triploid cells (Brown and Eckert 2005). As plants that are not fertile and not producing seeds, management efforts will not work if the flowers are targeted. Conversely, the plants in the Great Lakes region are generally diploid (Brown and Eckert 2005), and therefore their flowers are a valid means of reproduction for those plants and should also be targeted in eradication efforts. Flowering rush is not naturally controlled. It is not known to be a food source for many species beyond occasional grazing, so nothing is minimizing or hindering its spread within the ecosystems it is present; it is able to “function at its full biological potential in North America” (Oregon Department of Agriculture 2011).

Potential Ecological and Economic Impacts

Concern is growing about the effect of the spread of B. umbellatus in its non-

native regions. Once established, the efficient spread of the plant can quickly cause a wide variety of problems. Although no strong correlations have been discovered between the diversity of native species and exotic species establishment (Lavoie, Claude, et al. 2003), from an environmental perspective, conservationists and resource management officials still worry about its impact on native species (Minnesota Department of Natural Resources 2009). As any invasive species, its impact can be immediate in its competition for resources of the given environment. Since flowering rush can be somewhat aggressive in its spread, its threat to native species could increase as flowering rush can interrupt the native ecosystem interactions already in place. In some cases it has already been seen to outcompete native species of cattails and bulrushes (Oregon Department of Agriculture 2014).

As an invader of littoral ecosystems, including irrigation streams and drainage ditches (Oregon Department of Agriculture 2014), its growth can block these pathways (Figure 1, Bottom) and cause serious damage to agriculture if water is not reaching the crops or being drained from them properly. Their ability to cover densely and rapidly can pose a serious threat to irrigation systems and can hinder the ability to clear the plants out of these areas efficiently (Perkowski 2014). This can result in a loss of crops and indirectly cause further problems as an invasive species. At a recreational level, flowering rush can crowd shallow ponds and lakes, interfering with safe swimming and boating areas. Near-shore fishing has also seen impacts, as well as environmentally and economically important reservoirs that experience water level fluctuations (Oregon Department of Agriculture 2014). Economic impacts can result from all of these parts. The removal and eradication efforts can be very expensive themselves, and adding in the detrimental effects of flowering rush on the agriculture and aquatic recreation industry can inflict high financial cost to the economy.

Another indirect, yet very worrisome issue involves native fish of the Pacific Northwest, specifically threatened salmon and steelhead (Perkowski 2014). As temperatures cool in the fall and winter months, flowering rush falls to the riverbed but does not decompose. This allows pike eggs, another introduced and invasive species, to cling to the leaves and stems. Through this, the eggs are anchored and protected from suffocating in the mud.

Once hatched, these fish prey on native species and the aid from flowering rush provides further complications in their eradication (Perkowski 2014).

Management Strategies and Control Methods

Invasive Plant Management and Control

In order to determine the best strategies for control and management, an understanding of both the species’ life history as well as an understanding of the basic processes of an invasion is crucial. Three critical periods are involved in the establishment of an invasive plant: the introduction phase, the colonization phase, and the naturalization phase (Figure 8) (Radosevich 2002). The introduction phase begins with the initial individual plants that are likely to remain unnoticed by resource management officials during the period known as “lag time” (US Fish & Wildlife Service 2008). This time period is significant because it determines whether or not the plant has the proper resources available to survive. If the plant does survive, it enters the rapid reproduction stage of colonization, where officials are more likely to notice its establishment. Finally, once the population reaches a level it is able to sustain itself, it begins the naturalization phase. During this period, the population’s rapid expansion slows and it reaches stabilization (US Fish & Wildlife Service 2008).

Scientists have worked to develop methods that are most beneficial to each phase of the invasion process (Figure 8). These methods are Early Detection and Rapid Response (EDRR), Colonization, and Restoration

(Hobbs 1995, US Fish & Wildlife Service 2008). The prevention of introduction of an invasive species is the best form of control, but often times it is hard to regulate and species become introduced regardless. If

invasive species are identified soon enough, ideally EDRR will commence. Eradication efforts before the species has a chance to establish to the extent that it can reproduce more efficiently than it can be controlled are important. If the species has past this point and is entering the stage of colonization, the best alternative management approach would be to control its spread to a larger region. Eradication becomes less idyllic at this point and efforts should be focused on keeping the population contained and control. If the naturalization phase is reached, removal efforts become more unsuccessful and improbable. Sometimes small areas that are valuable to the community or environment may see restoration efforts, but this is usually not economically or financially feasible (Hobbs 1995, US Fish & Wildlife Service 2008).

Flowering Rush Management and Control

B. umbellatus has become more predominant in the northern United States and is now listed as state regulated in Washington, Idaho, Montana, Wisconsin, Vermont, New Hampshire, and Connecticut (Center for Invasive Species and Ecosystem Health 2010). It is banned in Connecticut and Minnesota, listed as a Class B noxious weed in Vermont (U.S.D.A., Natural Resource Conservation Service), and listed as a Class A noxious weed in Oregon (Oregon Department of Agriculture 2014). In Washington, areas of flowering rush are subject to quarantine to immediately eradicate and control the plant’s

Figure 8. The most effective management

strategies for each phase of the plant invasion

process: Early Detection and Rapid Response

(EDRR), Control, and Restoration (photo

credit: weedcenter.org).

establishment (U.S.D.A., Natural Resource Conservation Service). Various management approaches have been tried on B. umbellatus because of its diversity in reproductive strategies as well as the environments it is effecting. As a perennial, its reproduction through seeds, vegetative and clonal means can make control more difficult (US Fish & Wildlife Service 2008). Efforts of biocontrol are not very practical since flowering rush is not an attractive food source to animals in the region. It would not be grazed upon enough to mitigate its rapid growth, and in areas where it is a highly classified noxious weed, more serious efforts of control will usually be applied (Oregon Department of Agriculture 2008). For these reasons, other chemical and physical removal approaches are being investigated. Chemical treatments, although a generally popular method of weed control, have had mixed success. Herbicides are commonly washed away if the flowering rush is living along the shores of rivers. There are very limited chemicals that can be used in the presence of aquatic environments as well, and long exposure of the chemicals is also necessary for the best results. Since water can wash them away very easily, this decreases the possibility of eradication success (Perkowski 2014). Manual efforts also pose a variety of complications with the eradication of flowering rush. In order to be completely removed from the environment, every part of the plant needs to be removed from the sediment. Digging can be risky, since even a bulblet or rhizome fragment left behind has the opportunity to regrow and continue the spread of the population. This requires extensive and careful digging and often times many separate eradication efforts (Perkowski 2014, Jensen 2009). Cutting of the stalks is another approach to the control of invasive plants, but is not advised because of the disturbance it can cause to the rhizomes. Raking is also a common

method of invasive plant removal, but the same applies and it is not advised in the case of flowering rush (Jensen 2009). Flowering rush also resembles a plethora of native species when it is not in bloom, so to be able to legally remove it can require a special permit from the Department of Natural Resources (Minnesota Department of Natural Resources 2009). The most specialized treatment that has been debated is the use of bottom barriers. Some view these benthic nets, similar to

weed nets, as harmful to organisms that live in riverbeds or marshes (Department of Ecology of Washington State 2008), while others have seen general success in smaller environments or recreational areas (United States Department of Agriculture 2011).

Regardless of the method of removal, it is crucial to dispose of the plant waste properly in order to prevent spread from the removed fragments of the plant. Flowering rush should be thoroughly dried upon removal and should not be disposed of anywhere near aquatic environments, as roots can sprout and begin a new plant (Jensen 2009). It is also important for recreational boat users to wash and check their boats for flowering rush to avoid further introduction and spread (United States Department of Agriculture 2011).

Current Research and Management Efforts

Herbicides have been the main focus statewide on eradication and management of B. umbellatus. Trials in Michigan, Minnesota, Montana, and the Pacific Northwest have been extensive and ongoing (Aquatechnex 2013, Rice et al. 2009, Madsen et al. 2013).

In the Pacific Northwest, herbicides are being comprehensively studied in the application on populations of flowering rush (Figure 9). Aquatechnex, a community of scientists and biologists based in Arizona, California, Idaho, Montana, Oregon and Washington, have been working specifically

the United States Army Corps of Enginneers Aquatic Plant Control Research Program and SePRO Corporation to research the most effective methods of herbicide use (Aquatechnex 2013, Miller 2013). Their research has also commenced with the Whatcom County Noxious Weed Board in specialized treatments, and successes in laboratory treatments are now being tested in Idaho (Miller 2013). Herbicides such as Renovate® OTF granular, Reward® herbicide, Diquat aquatic herbicide, Renovate MAX G, and Clearcast have all shown overall positive results in suppressing B. umbellatus in the

Pacific Northwest (Aquatechnex 2013).

A study done in Montana has shown the variation of success after treatment with Habitat herbicide and Clearcast (Figure 10). Initial success is shown, but with the varying treatment you can see the regrowth of flowering rush beneath the surface. The Renovate herbicide was noticed to slow growth initially, but long-term results exhibited difficult distinction between treated patches and untreated patches (Rice 2009).

Figure 9. Top: Population of Flowering Rush

in Silver Lake, WA, Bottom: Application of

Renovate® OTF by Aquatechnex biologists

(photo credits: Aquatechnex).

These studies indicate the further need for research on herbicide treatments, since populations of flowering rush were shown to reestablish and remain invasive long-

term. A lot of progress has been made in the studies of management approaches of B. umbellatus, but additional research would help in determining even better possible eradication and management efforts. Works Cited

Aquatechnex 27 May 2011. First Large Scale Flowering Rush Treatment in Pacific Northwest Completed.

Aquatechnex. 30 Sept. 2013. Flowering Rush Control Work Continues in the Pacific Northwest.

Bargeron, C.T., C.R. Minteer, C.W. Evans, D.J. Moorhead, G.K. Douce and R.C. Reardon. Technical Coordinators. 2008. Invasive Plants of the United States: Identification, Biology and Control. USDA Forest Service. Forest Health Technology Enterprise Team. Morgantown, WV. FHTET-08-11.

Bhardwaj, Michael, and Christopher G. Eckert. 2001. Functional analysis of synchronous dichogamy in flowering

rush, Butomus umbellatus (Butomaceae). American Journal of Botany 88.12: 2204-2213.

Brown, Jeremy S., and Christopher G. Eckert. 2005. Evolutionary increase in sexual and clonal reproductive capacity during biological invasion in an aquatic plant Butomus umbellatus (Butomaceae). American Journal of Botany 92.3: 495-502.

Center for Invasive Species and Ecosystem Health. 4 May 2010. Flowering-rush, Butomus Umbellatus (Alismatales: Butomaceae). Center for Invasive Species and Ecosystem Health.

Core, Earl L. 1941. Butomus umbellatus in America.

Department of Ecology of Washington State. 2 November 2008. Written Findings of the Washington State Noxious Weed Control Board. Washington State Department of Agriculture.

EDDMapS. 2014. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health.

Hobbs, Richard J., and Stella E. Humphries. 1995. An integrated approach to the ecology and management of plant invasions. Conservation Biology 9.4: 761-770.

Hroudova, Zdenka, et al. 1996. The biology of Butomus umbellatus in shallow waters with fluctuating water level. Management and Ecology of Freshwater Plants. Springer Netherlands. 27-30.

Figure 10. Top: Untreated patch of B.

umbellatus in Flathead Lake, Montana,

Middle: Patch in Flathead Lake, Montana 409

days after low pool foliar spraying treatment of

Habitat herbicide, Bottom: Patch in Flathead

Lake, Montana 349 days after high pool foliar

spraying (“Note numerous shorter leaves of

flowering rush below the water”) (photo credit:

Rice 2009).

Indiana Department of Natural Resources. September 2013. Aquatic Invasive Species: Flowering Rush.

Invasive Species Program, Division of Ecological Resources. July 2009. Aquatic Invasive Species: Flowering Rush, Butomus Umbellatus. Minnesota Department of Natural Resources.

Jacobs, Jim, Jane Mangold, Hillary Parkinson, Virgil Dupuis, and Peter Rice. 1 September 2011. Cology and Management of Flowering Rush (Butomus Umbellatus L.). United States Department of Agriculture: Natural Resources Conservation Service.

Jensen, Doug. 13 February 2009. Flowering Rush (Butomus Umbellatus). University of Minnesota.

Oregon Department of Agriculture. 1 Oct. 2014. Flowering Rush, Butomus Umbellatus. Noxious Weed Control Program. Oregon Department of Agriculture.

Oregon Department of Agriculture. 2011. Plant Pest Risk Assessment for Flowering Rush, Butomus Umbellatus L. Oregon Department of Agriculture.

Lavoie, Claude, et al. 2003. Exotic plant species of the St. Lawrence River wetlands: a spatial and historical analysis. Journal of Biogeography 30.4: 537-549.

Lui, Keiko, Faye L. Thompson, and Christopher G. Eckert. 2005. Causes and consequences of extreme variation in reproductive strategy and vegetative growth among invasive populations of a clonal aquatic plant,

Butomus umbellatus L.(Butomaceae). Biological Invasions 7.3: 427-444.

Madsen, John D., et al. 2013. Herbicide Trials for Management of Flowering Rush in Detroit Lakes, Minnesota for 2012.

Montana Weed Control Association. 2009. Flowering Rush (Butomus Umbellatus L.). Montana Weed Control Association.

Perkowski, Mateusz. 3 October 2014. Irrigation-clogging Weed Arrives in Oregon. Capital Press.

Radosevich, Steve. 2002. Plant Invasions and Their Management. Chapter 3 in CIPM (ed.), Invasive Plant Management: CIPM Online Textbook. Bozeman, MT: Center for Invasive Plant Management.

Rice, P., Dupuis, V., Mitchell, A. 2009. Results in the Second Summer After Foliar Application of Herbicides to Flowering Rush. Duxbury Press.

Rice P., Dupuis V. 2008. Flowering rush: An invasive aquatic macrophyte infesting the headwaters of the Columbia River system. Northern Interior Columbia Basin Invasive Aquatic Plant Summit. Coeur d’ Alene, ID.

Sparrow, F. K. 1974. Observations on chytridiaceous parasites of phanerogams. XX. Resting spore germination and epibiotic stage of Physoderma butomi Schroeter. American Journal of Botany: 203-

208.

Steve, Miller. 6 August 2013. Flowering Rush Operational Research Program

Moves Forward. SePRO Coorporation.

Stevens, P. F. (2001 onwards). 12 July 2012. Angiosperm Phylogeny Website.

U.S.D.A., Natural Resource Conservation Service. 2014. Plant Profile for Butomus umbellatus (Flowering Rush).

United States of America. Department of the Interior: US Fish & Wildlife Service. 8 October 2008. Managing Invasive Plants. US Fish & Wildlife Service.

Key Resources

Department of Ecology of Washington State

http://www.ecy.wa.gov/programs/eap/lakes/

aquaticplants/butomusUmbellatus.pdf

Invasive Plant Management Textbook

http://www.weedcenter.org/textbook/

King County Noxious Weeds

www.kingcounty.gov/environment/animals

AndPlants/noxious-weeds

United States Department of Agriculture:

Natural Resources Conservation Service

http://www.nrcs.usda.gov/Internet/FSE_PL

ANTMATERIALS/publications/mtpmstn10

617.pdf

http://plants.usda.gov/java/profile?symbol=

BUUM

US Fish and Wildlife Service: National Wildlife Refuge System, Volunteers and Invasive Plants

http://www.fws.gov/invasives/volunteersTra

iningModule/index.html

Expert Contact Information in PNW

Reporting Invasive Species

Oregon Invasive Species Hotline: // 1-866-INVADER (866.468.2337)

Washington Invasive Species Hotline: // 1-877-9-INFEST (877.946.3378)

Washington State Department of Ecology

Aquatic Plant Specialist

Kathy Hamel // 360.407.6563

kham461@ecy.wa.gov

Aquatic Botanist

Jenifer K. Parsons

// 509.457.7136 jenp461@ecy.wa.gov

Oregon Department of Agriculture

Noxious Weed Program Manager

Tim Butler

// 503.986.4621

tbutler@oda.state.or.us

US Department of Agriculture Pest Program

Prevents establishment of high-risk and exotic insects, plant diseases and weeds through surveys, inspections, quarantines, and eradication projects; coordinates and administers state noxious weed program.

Dr. Jim Marra, Program Manager // 360.902.2071

Michele Gill, Administrative Assistant // 360.902.2070

Jennifer Falacy, Plant Pathology Project Coordinator // 360.586.5309