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 Control Association 2009). These flowers will either grow fruit that open at maturity Order: Alismatales and disperse seeds, or they will remain Family: Butomaceae sterile and reproduce through rhizomes and Genus: Butomus bulblets (Oregon Department of Agriculture Species: Butomus umbellatus 2014). These reproductive differences can Common names: Flowering Rush, Grassy also be assessed through their genes: Rush, Water Gladiolus diploid cells (2n = 2x = 26) produce a seeding plant and triploid cells (2n = 3x = Identification Key 36) produce a sterile plant (Department of Ecology of Washington State 2008). Seeds As a perennial Eurasian aquatic are adapted to float so they can be carried plant that exhibits characteristics from both along with the flow of the water (Center for the Cyperaceae and Juncaceae families Invasive Species and Ecosystem Health (Jacobs 2011), Butomus umbellatus is 2010). 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 Figure 2. Petal, stamen and pistil arrangement to grow in waters up to 20 feet (6 meters) of B. umbellatus (photo credit: Christian deep. The stems are green and triangular in Fischer, Cofrin Center for Biodiversity, cross section (Figure 3), generally grow up University of Wisconsin-Green Bay). to five feet (1.5 meters) tall, and are grounded by an extensive system of fibrous rhizomes (Oregon Department of B. umbellatus is predominantly and most Agriculture 2014). easily identified by its flowers, but when Depending on the depth of where the plant the plant is rooted in deeper waters it is located, it will either emerge and flower remains underwater and will therefore not or remain submerged. If the plant is produce any buds or flowers, making growing in shallower waters, it will grow identification much more difficult. When above the surface and produce radially submerged, the plant grows narrow and symmetric 1-inch light pink flowers in an limp triangular leaves that can reach up to umbrella-shaped formation (Figures 1, 2). about 3 feet (1 meter) long (Center for Each flower consists of six petals, six Invasive Species and Ecosystem Health 2010). This is opposed to the stiffer and pistils, and nine stamens arranged in two more supported leaves of the variety that whorls (Jacobs et al. 2011), which blossom grows above the surface, since those leaves between June and August (Montana Weed can twist and spiral toward the top of the plant (Jacobs et al. 2011). Both types, the photosynthetic processes (US Fish & underwater variation specifically, can also Wildlife Service 2008). be identified by the bulblets that form on the roots. These bulblets are the primary Reproductive Strategies form of reproduction for the submerged and As a perennial, the life cycle of B. sterile plants, and when the rhizomes are umbellatus can last for many years, and disturbed the buds are able to break off and although it produces fewer seeds compared produce new plants (Jensen 2009). 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

Figure 3. Triangular cross section of B. produce a fruit containing seeds (Figure 4). When the flowers have reached their sexual umbellatus stems (photo credit: Gary maturity, the fruit opens and releases the Fewless, University of Wisconsin, seeds into the environment (Oregon

Department of Agriculture 2014). Seeds Green Bay, Wisconsin). increase the distance of dispersal and

establishment due to their adaptation to Life History float on the water’s surface (Center for

Invasive Species and Ecosystem Health Life Cycle 2010). If the water is moving via a light The life cycle of B. umbellatus current, the seeds can be carried greater parallels that of any monocot in that it distances, which can lead to more begins as a seedling, grows and develops widespread invasions. In a case study of B. stems, leaves, and roots, and matures into a umbellatus, it was also found that each flowering plant. From there, the flowers flower is protandrous, therefore reducing produce seeds, which germinate once dispersed and become seedlings again (US the risk of self-pollination (Bhardwaj and Eckert 2001) and increasing successful Fish & Wildlife Service 2008). reproduction rates through seed production.

Feeding Habits Vegetative reproduction is another Vascular plants such as flowering significant form of reproduction of B. rush feed through their root system and umbellatus. Vegetative reproduction occurs shoot system. The fibrous roots collect when a plant regrows from something that nutrients from intake from the soil and the has been separated from the original plant, shoot system uses its leaves to capture the in this case, fragments of the rhizomes or suns light and extract nutrients from bulblets. (US Fish & Wildlife Service 2008). 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 Figure 5. B. umbellatus rhizome detail frequent disturbances in the environment (Jacobs et al. 2011). (photo credit: Bargeron 2008). The advantages of these two methods of asexual reproduction are the benefits of quick and immediate dispersal. Adjacent Environmental Tolerances plants can be established quickly and easily B. umbellatus is an indigenous plant since bulblets and rhizomes are already to Europe and Asia that thrives in areas of rooted in the substrate, and populations can slow-moving or relatively stagnant water grow rapidly without the waiting time for (Core 1941). It is known to be tolerant to a flowers to blossom and fruits to mature. great temperature range and therefore has a The disadvantage however, is the absence higher probability of establishing in of reproductive variation since no genes are differing climates (Center for Invasive being exchanged between individual plants. Species and Ecosystem Health 2010). It is This can reduce fitness if the plants are most commonly found in shallower waters facing changes in the ecosystem that require and especially areas with fluctuating water adaptation. With methods of sexual levels such as wetlands, irrigation ditches, reproduction, the plant is able to account and the shores of lakes. for these changes and can adapt to better These shallow areas of near-standing water suit the environment. Disadvantages of are more prone to the successful growth of sexual reproduction would include the rhizomes and bulblets because when the complications of pollination dependency water levels lower or when they completely and the chances of unsuccessful seed dissipate, the sun warms the ground. Since establishment. 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).

Biotic Associations Current Geographic Distribution The parasite physoderma butomi Schroeter was discovered on leaves of B. Although widespread throughout umbellatus in 1883 in Lake Michigan Asia and Europe, B. umbellatus has (Sparrow 1974). The resting spores generally only been reported in the northern generally infect the plant on the part of the United States. It has been subepidermal level of the leaves rather than documented in Washington, Idaho, the epidermis layer itself, and were also Montana, North Dakota, South Dakota, noted to infect the stalks of inflorescences. Nebraska, Kansas, Minnesota, Iowa, From a flat colony of the fungus, a Wisconsin, Illinois, Michigan, Indiana, zoospore will develop and germinate. When Ohio, Pennsylvania, New York, Vermont, this occurs, the zoospore bursts and is New Hampshire, Maine, Massachusetts, released into the water in which it attaches and Connecticut (Figure 6). to seedlings and beings to invade, In Washington State, it has been reported at continuing the infectious cycle (Sparrow these various sites and in these counties: 1974). No further critical research has been Columbia River (Tricities) (Benton), Long done on parasites or pathogens of B. (Spokane), Nine Mile (Spokane), Pend umbellatus, but it has been noted that Oreille R (Pend Orielle), Shaver (Pierce), aquatic environments containing flowering Silver (Whatcom), Yakima River (Benton), rush support great pond snail populations. and Yakima River (Prosser) (Benton) These snails host a parasite that has been (Figure 7). identified as a cause of ‘swimmer’s itch’ (Jacobs et al. 2011).

Figure 6. Documented Cases in United States (photo credit: EDDMapS, University of Georgia - Center for Invasive Species and Ecosystem Health).

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 Figure 7. Locations of WA Department of the invasion of other regions due to the possible introduction of the plant as a food Ecology survey sites. B. umbellatus was found at source for waterfowl (Core 1941, 8 sites (black marks) out of the 534 surveyed (red Department of Ecology of Washington State and yellow marks) (photo credit: Department of 2008). Studies show that the diploid plants originated from Europe and Asia and that Ecology of Washington State). the triploid plants originated from the Netherlands and Northern Germany History of Invasion (Department of Ecology of Washington State 2008). Regardless of the reason of The first recorded evidence of B. introduction, all are the effects of pathways umbellatus in North America was in 1897 of human involvement. in Canada along the St. Lawrence River. In the United States, it was first observed in Factors Influencing Establishment and the early 1900s and an early case of Spread establishment in Lake Champlain, New The biggest factor concerning the York was published in 1929 (Brown and spread of B. umbellatus is its varying Eckert 2005). Over the next decade it was methods of reproduction. The vegetative seen to be spreading throughout Vermont, reproduction strategies of this plant prove to Ohio, Michigan, and even West Virginia. make spread very easy and constant when In the Northwest, its introduction is rhizome systems are disrupted, which can believed to be from the invasion in Peaceful be often depending on the ecosystem it is Bay, Flathead Lake, Montana, in 1964. established (US Fish & Wildlife Service From there it was carried along the Flathead 2008). River and Clark Fork River to Lake Pend As mentioned before, vegetative Oreille in Idaho. The Pend Oreille River reproduction occurs when a portion of the then continued to carry it into Washington original plant is broken off or separated and State in the late 1990s, and today concern is a new plant is able to grow from the growing about its spread toward the shores fragment that has been removed. This, of the Columbia River (Department of paired with annual production of seeds in Ecology of Washington State 2008, Jacobs diploid plants, can create a high-impact 2011). cycle of the spread of flowering rush. An interesting observation to note is that Invasion Processes the geographic distribution varies between the fertile and sterile B. umbellats Pathways, Vectors and Routes of populations, leading to the need for Introduction different management and eradication approaches (Department of Ecology of As an invader of littoral ecosystems, Washington State 2008). including irrigation streams and drainage In North America, the plants identified in ditches (Oregon Department of Agriculture the northwest have been found to consist of 2014), its growth can block these pathways triploid cells (Brown and Eckert 2005). As (Figure 1, Bottom) and cause serious plants that are not fertile and not producing damage to agriculture if water is not seeds, management efforts will not work if reaching the crops or being drained from the flowers are targeted. Conversely, the them properly. Their ability to cover plants in the Great Lakes region are densely and rapidly can pose a serious generally diploid (Brown and Eckert 2005), threat to irrigation systems and can hinder and therefore their flowers are a valid the ability to clear the plants out of these means of reproduction for those plants and areas efficiently (Perkowski 2014). This should also be targeted in eradication can result in a loss of crops and indirectly efforts. cause further problems as an invasive Flowering rush is not naturally controlled. It species. At a recreational level, flowering is not known to be a food source for many rush can crowd shallow ponds and lakes, species beyond occasional grazing, so interfering with safe swimming and boating nothing is minimizing or hindering its areas. Near-shore fishing has also seen spread within the ecosystems it is present; it impacts, as well as environmentally and is able to “function at its full biological economically important reservoirs that potential in North America” (Oregon experience water level fluctuations (Oregon Department of Agriculture 2011). Department of Agriculture 2014). Economic impacts can result from all of Potential Ecological and Economic Impacts these parts. The removal and eradication Concern is growing about the effect efforts can be very expensive themselves, of the spread of B. umbellatus in its non- and adding in the detrimental effects of native regions. Once established, the flowering rush on the agriculture and efficient spread of the plant can quickly aquatic recreation industry can inflict high cause a wide variety of problems. financial cost to the economy. Although no strong correlations have been Another indirect, yet very worrisome issue discovered between the diversity of native involves native fish of the Pacific species and exotic species establishment Northwest, specifically threatened salmon (Lavoie, Claude, et al. 2003), from an and steelhead (Perkowski 2014). As environmental perspective, conservationists temperatures cool in the fall and winter and resource management officials still months, flowering rush falls to the riverbed worry about its impact on native species but does not decompose. This allows pike (Minnesota Department of Natural eggs, another introduced and invasive Resources 2009). As any invasive species, species, to cling to the leaves and stems. its impact can be immediate in its Through this, the eggs are anchored and competition for resources of the given protected from suffocating in the mud. environment. Since flowering rush can be Once hatched, these fish prey on native somewhat aggressive in its spread, its threat species and the aid from flowering rush to native species could increase as provides further complications in their flowering rush can interrupt the native eradication (Perkowski 2014). 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). Management Strategies and Control Scientists have worked to develop methods Methods that are most beneficial to each phase of the invasion process (Figure 8). These methods Invasive Plant Management and Control are Early Detection and Rapid Response In order to determine the best (EDRR), Colonization, and Restoration strategies for control and management, an (Hobbs 1995, US Fish & Wildlife Service understanding of both the species’ life 2008). The prevention of introduction of an history as well as an understanding of the invasive species is the best form of control, basic processes of an invasion is crucial. but often times it is hard to regulate and Three critical periods are involved in the species become introduced regardless. If establishment of an invasive plant: the invasive species are identified soon enough, introduction phase, the colonization phase, ideally EDRR will commence. Eradication and the naturalization phase (Figure 8) efforts before the species has a chance to (Radosevich 2002). The introduction phase establish to the extent that it can reproduce begins with the initial individual plants that more efficiently than it can be controlled are likely to remain unnoticed by resource are important. If the species has past this management officials during the period point and is entering the stage of known as “lag time” (US Fish & Wildlife colonization, the best alternative Service 2008). This time period is management approach would be to control significant because it determines whether or its spread to a larger region. Eradication not the plant has the proper resources becomes less idyllic at this point and efforts available to survive. If the plant does should be focused on keeping the survive, it enters the rapid reproduction population contained and control. If the stage of colonization, where officials are naturalization phase is reached, removal more likely to notice its establishment. efforts become more unsuccessful and Finally, once the population reaches a level improbable. Sometimes small areas that are it is able to sustain itself, it begins the valuable to the community or environment naturalization phase. During this period, the may see restoration efforts, but this is population’s rapid expansion slows and it usually not economically or financially reaches stabilization (US Fish & Wildlife feasible (Hobbs 1995, US Fish & Wildlife Service 2008). 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 Figure 8. The most effective management (Oregon Department of Agriculture 2014). strategies for each phase of the plant invasion In Washington, areas of flowering rush are subject to quarantine to immediately process: Early Detection and Rapid Response eradicate and control the plant’s (EDRR), Control, and Restoration (photo credit: weedcenter.org). establishment (U.S.D.A., Natural Resource method of invasive plant removal, but the Conservation Service). same applies and it is not advised in the Various management approaches have been case of flowering rush (Jensen 2009). tried on B. umbellatus because of its Flowering rush also resembles a plethora of diversity in reproductive strategies as well native species when it is not in bloom, so to as the environments it is effecting. As a be able to legally remove it can require a perennial, its reproduction through seeds, special permit from the Department of vegetative and clonal means can make Natural Resources (Minnesota Department control more difficult (US Fish & Wildlife of Natural Resources 2009). Service 2008). Efforts of biocontrol are not The most specialized treatment that has very practical since flowering rush is not an been debated is the use of bottom barriers. attractive food source to animals in the Some view these benthic nets, similar to region. It would not be grazed upon enough weed nets, as harmful to organisms that live to mitigate its rapid growth, and in areas in riverbeds or marshes (Department of where it is a highly classified noxious Ecology of Washington State 2008), while weed, more serious efforts of control will others have seen general success in smaller usually be applied (Oregon Department of environments or recreational areas (United Agriculture 2008). For these reasons, other States Department of Agriculture 2011). chemical and physical removal approaches Regardless of the method of removal, it is are being investigated. crucial to dispose of the plant waste Chemical treatments, although a generally properly in order to prevent spread from the popular method of weed control, have had removed fragments of the plant. Flowering rush should be thoroughly dried upon mixed success. Herbicides are commonly removal and should not be disposed of washed away if the flowering rush is living anywhere near aquatic environments, as along the shores of rivers. There are very roots can sprout and begin a new plant limited chemicals that can be used in the (Jensen 2009). It is also important for presence of aquatic environments as well, recreational boat users to wash and check and long exposure of the chemicals is also their boats for flowering rush to avoid necessary for the best results. Since water further introduction and spread (United can wash them away very easily, this States Department of Agriculture 2011). decreases the possibility of eradication success (Perkowski 2014). Current Research and Management Manual efforts also pose a variety of Efforts complications with the eradication of flowering rush. In order to be completely Herbicides have been the main removed from the environment, every part focus statewide on eradication and of the plant needs to be removed from the management of B. umbellatus. Trials in sediment. Digging can be risky, since even Michigan, Minnesota, Montana, and the a bulblet or rhizome fragment left behind Pacific Northwest have been extensive and has the opportunity to regrow and continue ongoing (Aquatechnex 2013, Rice et al. the spread of the population. This requires 2009, Madsen et al. 2013). extensive and careful digging and often In the Pacific Northwest, herbicides are times many separate eradication efforts being comprehensively studied in the (Perkowski 2014, Jensen 2009). Cutting of application on populations of flowering rush the stalks is another approach to the control (Figure 9). Aquatechnex, a community of of invasive plants, but is not advised scientists and biologists based in Arizona, because of the disturbance it can cause to California, Idaho, Montana, Oregon and the rhizomes. Raking is also a common Washington, have been working specifically the United States Army Corps of A study done in Montana has shown the Enginneers Aquatic Plant Control Research variation of success after treatment with Program and SePRO Corporation to Habitat herbicide and Clearcast (Figure 10). research the most effective methods of Initial success is shown, but with the herbicide use (Aquatechnex 2013, Miller varying treatment you can see the regrowth 2013). Their research has also commenced of flowering rush beneath the surface. The with the Whatcom County Noxious Weed Renovate herbicide was noticed to slow Board in specialized treatments, and growth initially, but long-term results successes in laboratory treatments are now exhibited difficult distinction between being tested in Idaho (Miller 2013). treated patches and untreated patches (Rice Herbicides such as Renovate® OTF 2009). 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).

Figure 9. Top: Population of Flowering Rush in Silver Lake, WA, Bottom: Application of Renovate® OTF by Aquatechnex biologists (photo credits: Aquatechnex).

rush, Butomus umbellatus Figure 10. Top: Untreated patch of B. (Butomaceae). American Journal of umbellatus in Flathead Lake, Montana, Botany 88.12: 2204-2213.

Middle: Patch in Flathead Lake, Montana 409 Brown, Jeremy S., and Christopher G. days after low pool foliar spraying treatment of Eckert. 2005. Evolutionary increase Habitat herbicide, Bottom: Patch in Flathead in sexual and clonal reproductive capacity during biological invasion in Lake, Montana 349 days after high pool foliar an aquatic plant Butomus umbellatus spraying (“Note numerous shorter leaves of (Butomaceae). American Journal of flowering rush below the water”) (photo credit: Botany 92.3: 495-502.

Rice 2009). Center for Invasive Species and Ecosystem Health. 4 May 2010. Flowering-rush, Butomus Umbellatus (Alismatales: These studies indicate the further need for Butomaceae). Center for Invasive research on herbicide treatments, since Species and Ecosystem Health. populations of flowering rush were shown to reestablish and remain invasive long- Core, Earl L. 1941. Butomus umbellatus in term. A lot of progress has been made in America. the studies of management approaches of B. umbellatus, but additional research would Department of Ecology of Washington help in determining even better possible State. 2 November 2008. Written eradication and management efforts. Findings of the Washington State Noxious Weed Control Board. Works Cited Washington State Department of Agriculture. Aquatechnex 27 May 2011. First Large Scale Flowering Rush Treatment in EDDMapS. 2014. Early Detection & Pacific Northwest Completed. Distribution Mapping System. The University of Georgia - Center for Aquatechnex. 30 Sept. 2013. Flowering Invasive Species and Ecosystem Rush Control Work Continues in the Health. Pacific Northwest. Hobbs, Richard J., and Stella E. Bargeron, C.T., C.R. Minteer, C.W. Evans, Humphries. 1995. An integrated D.J. Moorhead, G.K. Douce and R.C. approach to the ecology and Reardon. Technical Coordinators. management of plant invasions. 2008. Invasive Plants of the United Conservation Biology 9.4: 761-770. States: Identification, Biology and Control. USDA Forest Service. Forest Hroudova, Zdenka, et al. 1996. The biology Health Technology Enterprise Team. of Butomus umbellatus in shallow Morgantown, WV. FHTET-08-11. waters with fluctuating water level. Management and Ecology of Bhardwaj, Michael, and Christopher G. Freshwater Plants. Springer Eckert. 2001. Functional analysis of Netherlands. 27-30. synchronous dichogamy in flowering Indiana Department of Natural Resources. Butomus umbellatus L.(Butomaceae). September 2013. Aquatic Invasive Biological Invasions 7.3: 427-444. Species: Flowering Rush. Madsen, John D., et al. 2013. Herbicide Invasive Species Program, Division of Trials for Management of Flowering Ecological Resources. July 2009. Rush in Detroit Lakes, Minnesota for Aquatic Invasive Species: Flowering 2012. Rush, Butomus Umbellatus. Minnesota Department of Natural Montana Weed Control Association. 2009. Resources. Flowering Rush (Butomus Umbellatus L.). Montana Weed Jacobs, Jim, Jane Mangold, Hillary Control Association. Parkinson, Virgil Dupuis, and Peter Rice. 1 September 2011. Cology and Perkowski, Mateusz. 3 October 2014. Management of Flowering Rush Irrigation-clogging Weed Arrives in (Butomus Umbellatus L.). United Oregon. Capital Press. States Department of Agriculture: Natural Resources Conservation Radosevich, Steve. 2002. Plant Invasions Service. and Their Management. Chapter 3 in Jensen, Doug. 13 February 2009. Flowering CIPM (ed.), Invasive Plant Rush (Butomus Umbellatus). Management: CIPM Online University of Minnesota. Textbook. Bozeman, MT: Center for Invasive Plant Management.

Oregon Department of Agriculture. 1 Oct. Rice, P., Dupuis, V., Mitchell, A. 2009. 2014. Flowering Rush, Butomus Results in the Second Summer After Umbellatus. Noxious Weed Control Foliar Application of Herbicides to Program. Oregon Department of Flowering Rush. Duxbury Press. Agriculture. Rice P., Dupuis V. 2008. Flowering rush: Oregon Department of Agriculture. 2011. An invasive aquatic macrophyte Plant Pest Risk Assessment for infesting the headwaters of the Flowering Rush, Butomus Umbellatus Columbia River system. Northern L. Oregon Department of Agriculture. Interior Columbia Basin Invasive Aquatic Plant Summit. Coeur d’ Lavoie, Claude, et al. 2003. Exotic plant Alene, ID. species of the St. Lawrence River wetlands: a spatial and historical Sparrow, F. K. 1974. Observations on analysis. Journal of Biogeography chytridiaceous parasites of 30.4: 537-549. phanerogams. XX. Resting spore germination and epibiotic stage of Lui, Keiko, Faye L. Thompson, and Physoderma butomi Schroeter. Christopher G. Eckert. 2005. Causes American Journal of Botany: 203- and consequences of extreme 208. variation in reproductive strategy and vegetative growth among invasive Steve, Miller. 6 August 2013. Flowering populations of a clonal aquatic plant, Rush Operational Research Program Moves Forward. SePRO http://www.fws.gov/invasives/volunteersTra Coorporation. iningModule/index.html

Stevens, P. F. (2001 onwards). 12 July Expert Contact Information in PNW 2012. Angiosperm Phylogeny Website. Reporting Invasive Species

U.S.D.A., Natural Resource Conservation Oregon Invasive Species Hotline: Service. 2014. Plant Profile for // 1-866-INVADER (866.468.2337) Butomus umbellatus (Flowering Rush). Washington Invasive Species Hotline: // 1-877-9-INFEST (877.946.3378) United States of America. Department of Washington State Department of Ecology the Interior: US Fish & Wildlife

Service. 8 October 2008. Managing Aquatic Plant Specialist Invasive Plants. US Fish & Wildlife Kathy Hamel Service. // 360.407.6563 [email protected] Key Resources

Aquatic Botanist Department of Ecology of Washington State Jenifer K. Parsons

// 509.457.7136 http://www.ecy.wa.gov/programs/eap/lakes/ [email protected] aquaticplants/butomusUmbellatus.pdf

Oregon Department of Agriculture Invasive Plant Management Textbook

Noxious Weed Program Manager http://www.weedcenter.org/textbook/ Tim Butler

// 503.986.4621 King County Noxious Weeds [email protected] www.kingcounty.gov/environment/animals

AndPlants/noxious-weeds US Department of Agriculture Pest Program

United States Department of Agriculture: Prevents establishment of high-risk and Natural Resources Conservation Service exotic insects, plant diseases and weeds http://www.nrcs.usda.gov/Internet/FSE_PL through surveys, inspections, quarantines, ANTMATERIALS/publications/mtpmstn10 and eradication projects; coordinates and 617.pdf administers state noxious weed program. http://plants.usda.gov/java/profile?symbol= Dr. Jim Marra, Program Manager BUUM // 360.902.2071 Michele Gill, Administrative Assistant US Fish and Wildlife Service: National // 360.902.2070 Wildlife Refuge System, Volunteers and Jennifer Falacy, Plant Pathology Project Invasive Plants Coordinator // 360.586.5309