"Problem solved," one might think; artists can harvest the material for their own use and help the environment at the same time. If only it were that simple. As coordinator of the Florida Invasive Plant Education Initiative, I am surrounded by an abundance of information on the risks associated with harvesting and using invasive plants.1 Kozo is one of 130 plant species considered invasive in Florida.2 In 2004–2005, over $37 million were spent controlling invasive plant species in the state's aquatic, wetland, and terrestrial habitats.3 While the big dollar figure is alarming, it is the hundreds of photographs that have come across my desk that worry me the most—images of invasive species gone wild, covering forests, lakes, rivers, or wetlands, choking out native flora and fauna and threatening Florida's biodiversity. Trips to field sites, where a single species has created a monoculture biodiversity. Trips to field sites, where a single species has created a monoculture as far as the eye can see, have left a lasting impression. as far as the eye can see, have left a lasting impression. A Papermaker's Dilemma: A Papermaker's Dilemma: Examining the Use of Examining the Use of Invasive Plants Invasive Plants amy richard amy richard Paper mulberry (Broussonetia papyrifera or kozo) can Paper mulberry (Broussonetia papyrifera or kozo) can be found growing in abandoned lots and disturbed lands be found growing in abandoned lots and disturbed lands in northeast central Florida. This photograph, taken in in northeast central Florida. This photograph, taken in September 2009, shows a perfect example of how the plant September 2009, shows a perfect example of how the plant crowds out native species like the wax myrtle (pictured in the crowds out native species like the wax myrtle (pictured in the center), eventually creating a monoculture. All photos by center), eventually creating a monoculture. All photos by and courtesy of the author, taken in Gainesville, Florida. and courtesy of the author, taken in Gainesville, Florida. 24 • hand papermaking 24 - hand papermaking Paper mulberry plants have highly variable leaves ranging in size from 3 to 10 Paper mulberry plants have highly variable leaves ranging in size from 3 to 10 inches long. A combination of leaf shapes may be found on one plant or they inches long. A combination of leaf shapes may be found on one plant or they may all be the same. Smaller leaves tend to be egg-shaped with pointed tips and may all be the same. Smaller leaves tend to be egg-shaped with pointed tips and serrated edges (margins). This tree is growing just outside the book and paper serrated edges (margins). This tree is growing just outside the book and paper studio at Penland School of Crafts in North Carolina. August 2009. studio at Penland School of Crafts in North Carolina. August 2009. Larger paper mulberry leaves tend to be heart or mitten shaped, some are deeply Larger paper mulberry leaves tend to be heart or mitten shaped, some are deeply notched with three large or two smaller lobes near the base of the leaf. Soft notched with three large or two smaller lobes near the base of the leaf. Soft hairs on the stems and leaf undersides are other distinguishing characteristics. hairs on the stems and leaf undersides are other distinguishing characteristics. November 2009. November 2009. It can be a prickly subject, which is why my intent is not to It can be a prickly subject, which is why my intent is not to preach but to present a yellow blinking light: a warning signal preach but to present a yellow blinking light: a warning signal for us to reduce speed and take a closer look before proceeding. for us to reduce speed and take a closer look before proceeding. As one scientist warns, "For invasive species, the stakes are higher As one scientist warns, "For invasive species, the stakes are higher than for most other forms of pollution because once a species is than for most other forms of pollution because once a species is established and has begun to spread, the introduction is irreversible." established and has begun to spread, the introduction is irreversible." 4 4 Unlike many agricultural and/or horticultural plants, some Unlike many agricultural and/or horticultural plants, some nonnative species are able to flourish outside of cultivation.5 Because nonnative species are able to flourish outside of cultivation.5 Because these plants are beyond their native range, their natural these plants are beyond their native range, their natural enemies (e.g., bacteria, fungi, insects, herbivores) are not present, enemies (e.g., bacteria, fungi, insects, herbivores) are not present, giving them a huge advantage and allowing them to cover or giving them a huge advantage and allowing them to cover or shade out native plants and/or drive away native wildlife that have shade out native plants and/or drive away native wildlife that have evolved within an ecosystem.6 Once the presence of a nonnative evolved within an ecosystem.6 Once the presence of a nonnative species results in economic or environmental harm to human, species results in economic or environmental harm to human, animal, or plant health, it is defined as invasive.7 Throughout the animal, or plant health, it is defined as invasive.7 Throughout the United States, invasive species (including animals) are causing United States, invasive species (including animals) are causing environmental damage and losses totaling an estimated $137 billion environmental damage and losses totaling an estimated $137 billion per year.8 per year.8 Like many of the invasive plants that we are trying to control Like many of the invasive plants that we are trying to control today, kozo was introduced into the United States with the best of today, kozo was introduced into the United States with the best of intentions. One source dates its introduction in Virginia as early intentions. One source dates its introduction in Virginia as early as the 1830s as a potential papermaking fiber, back when the number as the 1830s as a potential papermaking fiber, back when the number of American paper mills was growing and sources for cotton of American paper mills was growing and sources for cotton rag were dwindling.9 Since then, it has become naturalized—reproducing rag were dwindling.9 Since then, it has become naturalized—reproducing on its own outside of cultivation—in many neighboring on its own outside of cultivation—in many neighboring states. In numerous instances, this is the first step towards states. In numerous instances, this is the first step towards becoming invasive. In Florida, kozo plants were reported as early becoming invasive. In Florida, kozo plants were reported as early as 1903.10 It is now documented in every corner of the state.11 as 1903.10 It is now documented in every corner of the state.11 The degree of kozo's invasiveness depends on region, climate, The degree of kozo's invasiveness depends on region, climate, and soils. The USDA Plants Database documents the occurrence and soils. The USDA Plants Database documents the occurrence of B. papyrifera in at least 29 states in the United States, but that of B. papyrifera in at least 29 states in the United States, but that does not mean that the plant has been assessed in every state.12 To does not mean that the plant has been assessed in every state.12 To date, it is considered invasive in natural areas in at least 11 of the date, it is considered invasive in natural areas in at least 11 of the 29 states: Florida, the District of Columbia, Georgia, Louisiana, 29 states: Florida, the District of Columbia, Georgia, Louisiana, Maryland, North Carolina, Oklahoma, Pennsylvania, South Carolina, Maryland, North Carolina, Oklahoma, Pennsylvania, South Carolina, Tennessee, and Virginia. Also, it is reported to be invasive in Tennessee, and Virginia. Also, it is reported to be invasive in more than a dozen other countries.13 more than a dozen other countries.13 Numerous state and federal publications agree on the negative Numerous state and federal publications agree on the negative environmental impacts of paper mulberry: environmental impacts of paper mulberry: • It exhibits aggressive growth, quickly invading open habitats - It exhibits aggressive growth, quickly invading open habitats such as forest and field edges or disturbed lands, displacing such as forest and field edges or disturbed lands, displacing and out-competing native vegetation; and out-competing native vegetation; • It negatively impacts wildlife dependent on native vegetation - It negatively impacts wildlife dependent on native vegetation for forage, nesting, and cover; 14 for forage, nesting, and cover; 14 • Its fruits can be spread significant distances by wildlife, enabling - Its fruits can be spread significant distances by wildlife, enabling it to spread deeply within undisturbed areas; it to spread deeply within undisturbed areas; • Once established, paper mulberry spreads from its root system, - Once established, paper mulberry spreads from its root system, forming dense thickets, which are often 30 feet across.15 forming dense thickets, which are often 30 feet across.15 In addition to producing thousands of seeds, mature paper In addition to producing thousands of seeds, mature paper mulberry trees, growing to heights of more than 30 feet, spread mulberry trees, growing to heights of more than 30 feet, spread vegetatively by sending up vertical shoots or "suckers" from underground vegetatively by sending up vertical shoots or "suckers" from underground stems (rhizomes) that reach as far as 30 feet from the stems (rhizomes) that reach as far as 30 feet from the parent plant. This shallow web-like system prevents other plants parent plant. This shallow web-like system prevents other plants from growing in the understory and results in a monoculture of from growing in the understory and results in a monoculture of paper mulberry. In every location where I have found it, this root paper mulberry. In every location where I have found it, this root system was present and seemed to extend even farther. system was present and seemed to extend even farther. With all of this said, B. papyrifera is, at the present, considered With all of this said, B. papyrifera is, at the present, considered to be somewhat less egregious when compared with other invasive to be somewhat less egregious when compared with other invasive species in Florida. According to the IFAS Assessment, used species in Florida. According to the IFAS Assessment, used by the University of Florida, Institute of Food and Agricultural by the University of Florida, Institute of Food and Agricultural Sciences (IFAS) to evaluate invasiveness in the state, paper mulberry Sciences (IFAS) to evaluate invasiveness in the state, paper mulberry "may be recommended with caution" and "managed [as] to "may be recommended with caution" and "managed \[as\] to prevent escape."16 Florida's Exotic Pest Plant Council (FLEPPC) ranks paper mulberry as a Category II species, "an invasive exotic prevent escape."16 Florida's Exotic Pest Plant Council (FLEPPC) ranks paper mulberry as a Category II species, "an invasive exotic that has increased in abundance or frequency but has not yet altered that has increased in abundance or frequency but has not yet altered Florida plant communities to the extent shown by Category I Florida plant communities to the extent shown by Category I species (i.e., positively invasive)." They follow up by stating, "This species (i.e., positively invasive)." They follow up by stating, "This species may become ranked as Category I, if ecological damage is species may become ranked as Category I, if ecological damage is demonstrated."17 demonstrated."17 B. papyrifera has not shown up yet on the Florida noxious weed B. papyrifera has not shown up yet on the Florida noxious weed list so it is not "officially" a problem to harvest it from existing list so it is not "officially" a problem to harvest it from existing stands.18 However, at least one individual in the plant management stands.18 However, at least one individual in the plant management arena is now considering recommending that kozo join the list.19 arena is now considering recommending that kozo join the list.19 If you are contemplating the use of kozo or another plant found If you are contemplating the use of kozo or another plant found somewhere other than on your own property, research may be warranted. somewhere other than on your own property, research may be warranted. Most states have laws limiting or restricting the transport Most states have laws limiting or restricting the transport or possession of certain plants; some require a permit, others are or possession of certain plants; some require a permit, others are prohibited altogether (i.e., illegal to possess or transport). Your prohibited altogether (i.e., illegal to possess or transport). Your state's noxious weed list is a good place to start. state's noxious weed list is a good place to start. Noxious weed lists and laws were created because harvesting Noxious weed lists and laws were created because harvesting known invasive plants can help to spread the plant, especially if known invasive plants can help to spread the plant, especially if seeds or fruit are present. Collecting material in the winter when seeds or fruit are present. Collecting material in the winter when the plant is dormant or before it produces seed or fruit can help the plant is dormant or before it produces seed or fruit can help reduce the risk. When harvesting an invasive or even a potentially reduce the risk. When harvesting an invasive or even a potentially invasive plant, it is also recommended that any extra material invasive plant, it is also recommended that any extra material be collected and disposed of properly, especially material with be collected and disposed of properly, especially material with attached seeds or spores, or plant parts capable of vegetative reproduction. attached seeds or spores, or plant parts capable of vegetative reproduction. 20 Some land managers have been known to use tarps 20 Some land managers have been known to use tarps or tight-meshed ground cloths for this purpose. Proper disposal or tight-meshed ground cloths for this purpose. Proper disposal involves burning, freezing, or putting all materials in household involves burning, freezing, or putting all materials in household trash that is destined for the landfill, far away from a compost pile. trash that is destined for the landfill, far away from a compost pile. As well, viable parts of invasive plant species should never be discarded As well, viable parts of invasive plant species should never be discarded with yard waste that may be provided as mulch to other with yard waste that may be provided as mulch to other homeowners. homeowners. For kozo specifically, the Japanese tradition of harvesting For kozo specifically, the Japanese tradition of harvesting branches in the winter seems to work although I have adopted the branches in the winter seems to work although I have adopted the practice of collecting and burning extra material in the backyard practice of collecting and burning extra material in the backyard fire pit as additional insurance. fire pit as additional insurance. When I first learned "Florida kozo" was invasive, I spent considerable When I first learned "Florida kozo" was invasive, I spent considerable time wondering if there was any way to safely cultivate it. time wondering if there was any way to safely cultivate it. Professor Ken Langeland, an invasive plant expert at the University Professor Ken Langeland, an invasive plant expert at the University of Florida, confirmed my suspicions with one word: "Don't." of Florida, confirmed my suspicions with one word: "Don't." In his opinion, kozo is one of the worst landscape weeds he has In his opinion, kozo is one of the worst landscape weeds he has seen.21 Like me, he battles to control the endless suckers that seen.21 Like me, he battles to control the endless suckers that sprout up all over his yard, new plants attached to underground sprout up all over his yard, new plants attached to underground rhizomes, all of which lead to a parent tree in a neighbor's yard. rhizomes, all of which lead to a parent tree in a neighbor's yard. Without removing the parent tree and all existing suckers, it is a Without removing the parent tree and all existing suckers, it is a futile effort. futile effort. His professional insight and my own personal experience His professional insight and my own personal experience with this plant further increase those twinges of guilt I experience with this plant further increase those twinges of guilt I experience when harvesting branches from local naturalized stands. If I when harvesting branches from local naturalized stands. If I care about the natural diversity of the habitats around my home, care about the natural diversity of the habitats around my home, shouldn't I be willing to permanently remove these plants, especially shouldn't I be willing to permanently remove these plants, especially in areas where they are clearly a problem? in areas where they are clearly a problem? While I have volunteered to remove other invasive plant species, While I have volunteered to remove other invasive plant species, I have not quite reached the point of treating a thriving stand I have not quite reached the point of treating a thriving stand of paper mulberry saplings with herbicides (i.e., the only viable of paper mulberry saplings with herbicides (i.e., the only viable way to control large infestations). But I'm close. After seeing some way to control large infestations). But I'm close. After seeing some Even this small shrubby-sized paper mulberry plant produces many fruits and Even this small shrubby-sized paper mulberry plant produces many fruits and consequently, seeds. Mature trees produce many more seeds in addition to consequently, seeds. Mature trees produce many more seeds in addition to spreading by horizontal underground stems (rhizomes) that sprout new plants or spreading by horizontal underground stems (rhizomes) that sprout new plants or "suckers" as far as 30 feet from the parent plant. This tree is growing outside the "suckers" as far as 30 feet from the parent plant. This tree is growing outside the book and paper studio at Penland School of Crafts in North Carolina. Small book and paper studio at Penland School of Crafts in North Carolina. Small suckers were observed by the author at least 40 feet from this tree. August 2009. suckers were observed by the author at least 40 feet from this tree. August 2009. Paper mulberry trunks are also quite variable. Some are pale brown or silvery Paper mulberry trunks are also quite variable. Some are pale brown or silvery gray in color. Others sport tiger stripes, shown here. Notice the absence of any gray in color. Others sport tiger stripes, shown here. Notice the absence of any ground vegetation, a product of its dense leaf canopy shading out the understory ground vegetation, a product of its dense leaf canopy shading out the understory and its shallow web of underground roots preventing other plants from growing. and its shallow web of underground roots preventing other plants from growing. November 2009. November 2009. 26 • hand papermaking 26 - hand papermaking of the local kozo populations, I have become increasingly uncomfortable of the local kozo populations, I have become increasingly uncomfortable with harvesting branches without also trying to remove with harvesting branches without also trying to remove the plant. Even though I am keen on access to such a wonderful the plant. Even though I am keen on access to such a wonderful fiber, I am also quite fond of Florida's beautiful and unique natural fiber, I am also quite fond of Florida's beautiful and unique natural areas, wild places that could be threatened by a monoculture of areas, wild places that could be threatened by a monoculture of paper mulberry. paper mulberry. Many of us, including me, are uncomfortable with the use of Many of us, including me, are uncomfortable with the use of chemicals in the natural environment. However, as I have learned chemicals in the natural environment. However, as I have learned from working at the Center for Aquatic and Invasive Plants, the from working at the Center for Aquatic and Invasive Plants, the research behind the use of herbicides is much more thorough than research behind the use of herbicides is much more thorough than in years past and regulations are far tougher. Working with a host in years past and regulations are far tougher. Working with a host of plant managers who are knowledgeable and dedicated to environmental of plant managers who are knowledgeable and dedicated to environmental safety has also increased my comfort level.22 safety has also increased my comfort level.22 For many plant infestations, herbicides have proven to be the For many plant infestations, herbicides have proven to be the only economical and ecological means of control, especially for only economical and ecological means of control, especially for plants like hydrilla, an aquatic species that can re-sprout from a plants like hydrilla, an aquatic species that can re-sprout from a tiny fragment fallen off a boat trailer and grow an inch or more a tiny fragment fallen off a boat trailer and grow an inch or more a day.23 The same is true for upland plants like the air potato vine, day.23 The same is true for upland plants like the air potato vine, which can grow up to eight inches in a day.24 There is really no which can grow up to eight inches in a day.24 There is really no way to effectively control these situations without herbicides. As way to effectively control these situations without herbicides. As well, other methods like the use of mechanical harvesters have well, other methods like the use of mechanical harvesters have their own problems, such as high mortality rates of fish and turtles their own problems, such as high mortality rates of fish and turtles killed in the machinery as it scoops up aquatic plant material.25 For killed in the machinery as it scoops up aquatic plant material.25 For this reason, virtually every governmental agency and many conservation this reason, virtually every governmental agency and many conservation organizations support or use herbicides as part of their organizations support or use herbicides as part of their toolbox for managing invasive vegetation. toolbox for managing invasive vegetation. When working with found plants, I have learned that it is always When working with found plants, I have learned that it is always a good idea to consult with the experts and there are plenty a good idea to consult with the experts and there are plenty who are ready to share their knowledge and expertise. They can be who are ready to share their knowledge and expertise. They can be found by contacting local or state environmental agencies or university found by contacting local or state environmental agencies or university cooperative extension services. Many states or regions have cooperative extension services. Many states or regions have native plant societies and pest plant councils that are comprised of native plant societies and pest plant councils that are comprised of plant management professionals. plant management professionals. To ease my own conflict with using invasive plants, I will continue To ease my own conflict with using invasive plants, I will continue to use "best management practices," and seek partnerships to use "best management practices," and seek partnerships with land managers in the area to coordinate my harvest along with with land managers in the area to coordinate my harvest along with their control efforts. And (sigh), I will also be exploring the cultivation their control efforts. And (sigh), I will also be exploring the cultivation and use of other non-invasive fibers such as flax or Dahlia…or and use of other non-invasive fibers such as flax or Dahlia…or perhaps, our native red mulberry. perhaps, our native red mulberry. "Florida kozo" saplings continue to sprout just steps from the author's studio and "Florida kozo" saplings continue to sprout just steps from the author's studio and 40 feet from a parent tree that was blown down during one of the many hurricanes 40 feet from a parent tree that was blown down during one of the many hurricanes that visited Florida in 2004. January 2010. that visited Florida in 2004. January 2010. A mature "parent" paper mulberry tree located two lots over from the author's A mature "parent" paper mulberry tree located two lots over from the author's house continues to introduce new plants to the neighborhood, in every direction. house continues to introduce new plants to the neighborhood, in every direction. February 2010. February 2010. ___________ ___________ notes notes 1. University of Florida/Institute of Food and Agricultural Sciences, Center for 1. University of Florida/Institute of Food and Agricultural Sciences, Center for Aquatic and Invasive Plants, http://plants.ifas.ufl.edu. Aquatic and Invasive Plants, http://plants.ifas.ufl.edu. 2. Florida Exotic Pest Plant Council, Florida Exotic Pest Plant Council Invasive 2. Florida Exotic Pest Plant Council, Florida Exotic Pest Plant Council Invasive Plant Lists, http://www.fleppc.org/list/list.htm (accessed February 24, 2010). Plant Lists, http://www.fleppc.org/list/list.htm (accessed February 24, 2010). 3. Kenneth A. Langeland, UF/IFAS Center for Aquatic and Invasive Plants, 3. Kenneth A. Langeland, UF/IFAS Center for Aquatic and Invasive Plants, personal comment to author, February 8, 2010. This figure includes both research personal comment to author, February 8, 2010. This figure includes both research and management costs. 4. David M. Lodge and Kristin Shrader-Frechette, "Non-indigenous Species: and management costs. 4. David M. Lodge and Kristin Shrader-Frechette, "Non-indigenous Species: Ecological Explanation, Environmental Ethics, and Public Policy," Conservation Ecological Explanation, Environmental Ethics, and Public Policy," Conservation Biology vol. 17, no. 1 (February 2003): 31–37. Biology vol. 17, no. 1 (February 2003): 31–37. 5. Nonnative describes any species that is present in a region outside its original, 5. Nonnative describes any species that is present in a region outside its original, historic range due to intentional or unintentional introduction; also referred to historic range due to intentional or unintentional introduction; also referred to as non-indigenous or exotic. The term nonnative does NOT necessarily mean it as non-indigenous or exotic. The term nonnative does NOT necessarily mean it is invasive. In Florida, the majority of an estimated 1,300 nonnative plant species is invasive. In Florida, the majority of an estimated 1,300 nonnative plant species are not causing problems. Some are beneficial. For more information, see are not causing problems. Some are beneficial. For more information, see Vic Ramey, "Non-Native Invasive Plants: An Introduction," from the Plant Management Vic Ramey, "Non-Native Invasive Plants: An Introduction," from the Plant Management in Florida Waters website, http://plants.ifas.ufl.edu/guide/invplant in Florida Waters website, http://plants.ifas.ufl.edu/guide/invplant .html#stewardship (accessed January 30, 2010). .html#stewardship (accessed January 30, 2010). 6. "Native" describes any species occurring naturally in a geographic region; also 6. "Native" describes any species occurring naturally in a geographic region; also referred to as indigenous. In the United States, plants are generally considered referred to as indigenous. In the United States, plants are generally considered native if they were here before the arrival of Europeans (i.e., Columbus). Source: native if they were here before the arrival of Europeans (i.e., Columbus). Source: Richard P. Wunderlin, © 2006 Institute for Systematic Botany, as quoted in the Richard P. Wunderlin, © 2006 Institute for Systematic Botany, as quoted in the Plant Management in Florida Waters website, http://plants.ifas.ufl.edu/guide/ Plant Management in Florida Waters website, http://plants.ifas.ufl.edu/guide/ invplant.html (accessed February 23, 2010). invplant.html (accessed February 23, 2010). 7. Invasive Species Definition Clarification and Guidance White Paper, Submitted 7. Invasive Species Definition Clarification and Guidance White Paper, Submitted by the Definitions Subcommittee of the Invasive Species Advisory Committee by the Definitions Subcommittee of the Invasive Species Advisory Committee (ISAC), for the National Invasive Species Council (April, 2006). The document, (ISAC), for the National Invasive Species Council (April, 2006). The document, available online, offers a great deal of information: http://www.invasivespecies.gov available online, offers a great deal of information: http://www.invasivespecies.gov /global/ISAC/ISAC_documents/ISAC%20Definititions%20White%20Paper%20 /global/ISAC/ISAC_documents/ISAC%20Definititions%20White%20Paper%20 %20-%20FINAL%20VERSION.pdf (accessed February 24, 2010). %20-%20FINAL%20VERSION.pdf (accessed February 24, 2010). 8. David Pimentel et al., "Environmental and Economic Costs of Nonindigenous 8. David Pimentel et al., "Environmental and Economic Costs of Nonindigenous Species in the United States," BioScience vol. 50, no. 1 (January 2000): 53–65. Species in the United States," BioScience vol. 50, no. 1 (January 2000): 53–65. 9. Edmund Fulling, "Botanical Aspects of the Paper-Pulp and Tanning Industries 9. Edmund Fulling, "Botanical Aspects of the Paper-Pulp and Tanning Industries in the United States—An Economic and Historical Survey," American Journal of in the United States—An Economic and Historical Survey," American Journal of Botany vol. 43, no. 8 (Oct. 1956): 621–634. Botany vol. 43, no. 8 (Oct. 1956): 621–634. 10. John Small, Flora of the Southeastern United States (New York: published 10. John Small, Flora of the Southeastern United States (New York: published by the author, 1903), 362. by the author, 1903), 362. 11. Eric Morgan and William Overholt, Wildland Weeds: Paper Mulberry, Broussonetia 11. Eric Morgan and William Overholt, Wildland Weeds: Paper Mulberry, Broussonetia papyrifera, University of Florida/IFAS Publication ENY-702 (Gainesville: papyrifera, University of Florida/IFAS Publication ENY-702 (Gainesville: Entomology and Nematology Department, Florida Cooperative Extension Service, Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, March 2004). Also available online at http://edis.ifas.ufl.edu/in498 (accessed February 24, 2010). Institute of Food and Agricultural Sciences, University of Florida, March 2004). Also available online at http://edis.ifas.ufl.edu/in498 (accessed February 24, 2010). 12. See profile of paper mulberry on the USDA Plants Database, http://plants 12. See profile of paper mulberry on the USDA Plants Database, http://plants .usda.gov/java/profile?symbol=BRPA4; and on the Invasive Plant Atlas of the .usda.gov/java/profile?symbol=BRPA4; and on the Invasive Plant Atlas of the United States, http://www.invasive.org/weedus/subject.html?sub=5208 (both accessed United States, http://www.invasive.org/weedus/subject.html?sub=5208 (both accessed February 24, 2010). February 24, 2010). 13. J.M. Swearingen, "Paper Mulberry," Alien Plant Working Group Least Wanted, 13. J.M. Swearingen, "Paper Mulberry," Alien Plant Working Group Least Wanted, on the Plant Conservation Alliance's website, http://www.nps.gov/plants/alien/ on the Plant Conservation Alliance's website, http://www.nps.gov/plants/alien/ fact/brpa1.htm (accessed February 24, 2010). fact/brpa1.htm (accessed February 24, 2010). 14. Lorraine Miller, Paper Mulberry, Broussonetia papyrifera, Invasive Plant 14. Lorraine Miller, Paper Mulberry, Broussonetia papyrifera, Invasive Plant Species, National Forests in Florida Protection Report R8-PR 46 (USDA Forest Species, National Forests in Florida Protection Report R8-PR 46 (USDA Forest Service, Southern Region, 2000). Service, Southern Region, 2000). 15. Eric Morgan and William Overholt, Wildland Weeds: Paper Mulberry, Broussonetia 15. Eric Morgan and William Overholt, Wildland Weeds: Paper Mulberry, Broussonetia papyrifera. See endnote 11. papyrifera. See endnote 11. 16. The University of Florida's IFAS Assessment project was created to provide recommendations 16. The University of Florida's IFAS Assessment project was created to provide recommendations concerning the use of nonnative plants in Florida. For more information, concerning the use of nonnative plants in Florida. For more information, see http://plants.ifas.ufl.edu/assessment/ (accessed December 10, 2009). see http://plants.ifas.ufl.edu/assessment/ (accessed December 10, 2009). 17. Florida Exotic Pest Plant Council (FLEPPC) is a non-governmental organization 17. Florida Exotic Pest Plant Council (FLEPPC) is a non-governmental organization comprised of plant management experts from around the state. One of their self-assigned comprised of plant management experts from around the state. One of their self-assigned tasks is to assist land-managers by setting priorities for invasive plant control tasks is to assist land-managers by setting priorities for invasive plant control programs through the maintenance and continuous review of the Invasive Plant programs through the maintenance and continuous review of the Invasive Plant Species, a biennial list supported by current ecological observations in the field plus Species, a biennial list supported by current ecological observations in the field plus information in several statewide plant databases and herbaria, http://www.fleppc. information in several statewide plant databases and herbaria, http://www.fleppc. org/list/list.htm (accessed January 20, 2010). Information specifically on kozo's org/list/list.htm (accessed January 20, 2010). Information specifically on kozo's classification in other states can be found from a number of resources, starting with classification in other states can be found from a number of resources, starting with these websites: http://plants.ifas.ufl.edu/node/634, http://www.naeppc.org/, and these websites: http://plants.ifas.ufl.edu/node/634, http://www.naeppc.org/, and http://www.eddmaps.org/species/ (all accessed February 24, 2010). http://www.eddmaps.org/species/ (all accessed February 24, 2010). 18. The Florida noxious weed list is available on the website of Florida Department 18. The Florida noxious weed list is available on the website of Florida Department of Agriculture and Consumer Services, Division of Plant Industry, http://www of Agriculture and Consumer Services, Division of Plant Industry, http://www .doacs.state.fl.us/pi/enpp/botany/noxweed.html (accessed February 10, 2010). .doacs.state.fl.us/pi/enpp/botany/noxweed.html (accessed February 10, 2010). 19. Ken Langeland, UF/IFAS Center for Aquatic and Invasive Plants, personal comment 19. Ken Langeland, UF/IFAS Center for Aquatic and Invasive Plants, personal comment to author, February 8, 2010. to author, February 8, 2010. 20. Ken Langeland, Help Protect Florida's Natural Areas from Non-Native Invasive 20. Ken Langeland, Help Protect Florida's Natural Areas from Non-Native Invasive Plants Circular 1204 (Gainesville: Agronomy Department, Florida Cooperative Plants Circular 1204 (Gainesville: Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Extension Service, Institute of Food and Agricultural Sciences, University of Florida, first published March 1998, revised February 2009). Also available online at http:// first published March 1998, revised February 2009). Also available online at http:// edis.ifas.ufl.edu/ag108 (accessed February 24, 2010). edis.ifas.ufl.edu/ag108 (accessed February 24, 2010). 21. Ken Langeland, UF/IFAS Center for Aquatic and Invasive Plants, personal comment 21. Ken Langeland, UF/IFAS Center for Aquatic and Invasive Plants, personal comment to author, February 2010. to author, February 2010. 22. For an interesting video presentation on the safety of herbicides, see Carole 22. For an interesting video presentation on the safety of herbicides, see Carole Lembi, "Why Aquatic Herbicides Affect Aquatic Plants and Not You!" on the website Lembi, "Why Aquatic Herbicides Affect Aquatic Plants and Not You!" on the website of the Department of Botany and Plant Pathology, Purdue University, http:// of the Department of Botany and Plant Pathology, Purdue University, http:// www.btny.purdue.edu/Aquatic/aquaticherb.html (accessed February 4, 2010). www.btny.purdue.edu/Aquatic/aquaticherb.html (accessed February 4, 2010). 23. Gerda Van Dijk et al., "Growth of Hygrophila and Hydrilla In Flowing Water," 23. Gerda Van Dijk et al., "Growth of Hygrophila and Hydrilla In Flowing Water," Journal of Aquatic Plant Management 24 (1986): 85–87. Journal of Aquatic Plant Management 24 (1986): 85–87. 24.Greg MacDonald, Jay Ferrell, Brent Sellers, Ken Langeland, Tina Duperron- 24.Greg MacDonald, Jay Ferrell, Brent Sellers, Ken Langeland, Tina Duperron- Bond, and Eileen Ketterer-Guest, Invasive Species Management Plans for Bond, and Eileen Ketterer-Guest, Invasive Species Management Plans for Florida, Circular 1529 (University of Florida, IFAS Extension, 2008). Also available Florida, Circular 1529 (University of Florida, IFAS Extension, 2008). Also available online at http://plants.ifas.ufl.edu/node/133 (accessed February 7, 2010). online at http://plants.ifas.ufl.edu/node/133 (accessed February 7, 2010). 25. Travis Booms, "Vertebrates Removed by Mechanical Weed Harvesting in Lake 25. Travis Booms, "Vertebrates Removed by Mechanical Weed Harvesting in Lake Keesus, Wisconsin," Journal of Aquatic Plant Management 37 (1999): 34–36. See Keesus, Wisconsin," Journal of Aquatic Plant Management 37 (1999): 34–36. See also William Haller et al., "Fish Harvest Resulting from Mechanical Control of also William Haller et al., "Fish Harvest Resulting from Mechanical Control of Hydrilla," Transactions of the American Fisheries Society 109 (1980): 517–520. Hydrilla," Transactions of the American Fisheries Society 109 (1980): 517–520.  

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