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Linking Ecology & Horticulture 
to Prevent Plant Invasions
Workshop News Codes of Conduct Workshop Proceedings
Select a group below to view their voluntary codes of conduct
Government Nursery Professionals Gardening Public Landscape Architects Botanic Gardens
and Arboreta
Voluntary Codes of Conduct for Botanic Gardens and Arboreta (PDF)

Current List of Endorsements of the Voluntary Codes of Conduct

American Nursery and Landscape Association

American Public Gardens Association

American Society of Landscape Architects

The American Society of Landscape Architects encourages its members to work with local ecologists, horticulturists, nurseries, botanic gardens, conservation organizations, and others to identify highly invasive, or potentially invasive, species, and develop management plans that provide solutions to problems caused by these species; keep current on invasive plant species issues through continuing education opportunities; do not specify or allow known invasive species on any projects where those species could contribute to the degradation of the environment; specify non-invasive species that are aesthetically and horticulturally suitable alternatives to invasive species in your region; encourage nurseries, suppliers, and others in the plant propagation industry to grow and provide only non-invasive plants; collaborate with local experts and agencies to develop and revise local landscape ordinances that will exclude regional invasive species; work with public officials to fund research and control of regional invasive non-native species on public lands; establish a regional environmental ethic for non-native invasive plants that identifies these species and educates citizens about the associated health and financial impacts; and encourage elected officials to fund removal or control of existing invasive species that threaten parks, open space, woodlands, and wetland ecosystems.

California Association of Nurseries and Garden Centers

California Association of Nurseries and Garden Centers’ efforts have been directed toward the California Horticultural Invasive Prevention (Cal-HIP) and its Plant Right campaign. In that effort they have distributed the initial brochure introducing the campaign to the group’s membership. The brochure identifies the problem of invasive plants and steps that can be taken to address the issue. One of the suggestions is for the individual nursery to adopt the Voluntary Codes of Conduct. They also have a prominent link on our home page to the Plant Right website. The goal of the program is to remove invasive plants from the nursery trade and recommend suitable alternatives.

Recently, CANGC’s endowment for scholarship and research (CANERS) funded a study of Pampas Grass cultivars. In certain regions Pampas Grass is a big problem but the issue of cultivars is still a question. They hope that this initial study will not only determine the invasive potential for Pampas Grass cultivars but also identify what factors need to be considered in this type of research.

California Invasive Plant Council

The California Invasive Plant Council is partnering with horticultural associations, agencies, and environmental groups to develop California's PlantRight Campaign, which promotes wildland-safe alternatives to invasive plants still found in the trade. Through the statewide speakers bureau, the Council will be spreading information on the campaign to garden clubs. They help guide research needed to support the collaborative. Cal-IPC also has published and distributed widely "Don't Plant a Pest!" brochures, a series suggesting wildland-safe alternatives for distinct regions of the state.

Chicago Botanic Garden (also implementing the Codes)

Connecticut Nursery and Landscape Association

Cornell Plantations

As a public garden, it is inherent in Cornell Plantations’ mission that we “preserve and enhance diverse horticultural collections and natural areas for the enrichment and education of the academic audience and the public.”
The primary purpose of this policy document and the recommendations within it is to balance our public garden mission of holding diverse horticultural collections with our conservation mission of preserving natural areas and the broader environment. This mission is further detailed in Plantations’ Envisioning Goals, which provides that Plantations “will serve as a model for the control of invasive plant species.”

The invasive species policy is based on the Voluntary Code of Conduct for Botanic Gardens and Arboreta, and will serve to direct how invasive plants are managed in Plantations’ collections.

Delaware Federation of Garden Clubs, member of National Garden Clubs, Inc.

Delaware Nursery & Landscape Association

The Delaware Nursery & Landscape Association has held numerous programs to educate the industry about the invasive plant issue. The DNLA has actively supported and participated in the Plants for a Livable Delaware initiative. The objective of Plants for a Livable Delaware is to reduce the purchase and use of invasive plants and increase the availability, purchase, and use of regionally appropriate landscape plants as well as facilitate the removal of invasive plants from privately-owned natural lands. Three brochures have been developed and distributed via this program. Plants for a Livable Delaware brochure features alternatives to invasive plants currently sold in the trade. The Controlling Backyard Invaders brochure focuses on control measures for invasive plants no longer sold but present in many natural areas. The newest publication, Livable Plants for the Home Landscape provides gardeners with the tools needed to use plants in attractive, sustainable combinations that are well adapted to specific niches in the landscape.

Denver Botanic Gardens

The Voluntary Codes of Conduct is part of Denver Botanic Gardens’ Collections Policy. When new plants are brought in and ready to be accessioned, the Plant Records department does a web search for invasiveness. Since 2007, the Water Hyacinth, Eichhornia crassipes, has been removed from the approved list for Plant Sale at DBG.

DBG is in the process of establishing horticultural trial gardens to test plants introduced through DBG’s plant introduction program ‘Plant Select®.’ Some of the trailing criteria will be to test for invasiveness before introduction.

DBG has representation in the Colorado Noxious Weed Advisory Committee, which provides advice to the Colorado Department of Agriculture on listing species. DBG does extensive research on invasive species ecology, control and restoration after weed control. DBG has published several stories in their members magazine, “In the Gardens” on the education of invasive species.

In February 2005 DBG displayed an art exhibit titled, “Illuminating Weeds” that included over 30 original pieces, including both scientific illustrations and artistic pieces of invasive species inspired by medieval book illuminations by the artist Annie Chappell. Interpretation for the month-long show included information about weeds and 3 5’ banners listing the Colorado state weed lists.

In the summers of 2005 and 2006 DBG designed, directed, and hosted the Applied Plant Conservation Training Program; an international professional development symposium and internship program in collaboration with the US Botanic Garden and CPC. This program reached over 50 professionals from 7 countries and 20 US states and included sessions on invasive species projects and discussion of the import of the Voluntary Codes.

In Spring 2006 DBG established a weed garden titled, “The Good, The Bad, and The Ugly”. This highly interpreted garden contained three sections: The Good- Native alternatives to invasive ornamentals, The Bad- Ornamentals that cause problems in wild areas, and The Ugly- Silk reproductions of invasive weeds. Signage explains the importance of invasive species and the impact of our planting choices. All were planted in containers to avoid spreading.

In 2005 DBG created a Rare Weeds of Colorado poster in collaboration with the Colorado Department of Agriculture. This poster highlights invasive species, which are currently rare in Colorado but have the potential to become large problems if left unnoticed.

Federated Garden Clubs of Iowa

The Federated Garden Clubs of Missouri, member of National Garden Clubs, Inc.

The Federated Garden Clubs of Missouri, a member of National Garden Clubs, Inc., recently saw the need for more invasive plant awareness and formed a new position, National Invasive Plants Education Chairman. All the clubs in Missouri are now encouraged to have at least one program on invasive plants and have educational displays at their flower shows. On a National level, one of the Chairman’s goals has been to have each of the 50 states and District of Columbia endorse the codes of conduct. Each club has also been encouraged to include the subject of invasive plants as a subject in NGC’s sponsored schools.

Florida Department of Transportation

Florida Nursery and Landscape Association

FNGLA was the first state association to officially endorse the Voluntary Code of Conduct. We urge nursery growers to embrace the code by incorporating its principles into their operations’ best management practices. The code is also explicitly referenced in FNGLA’s position paper on invasive species.

The Garden Club of America

Harold L. Lyon Arboretum

The Harold L. Lyon Arboretum is working to revise an early collections policy to include explicit steps to deal with invasive species on the garden’s grounds and to prevent the establishment of other non-native plants of concern. In addition, they are working closely with Dr. Shaheen Ansari, the weed risk assessment specialist at the University of Hawai’i at Manoa and with the O’ahu Invasive Species Council.

Ivy Removal Project

Jacksonville Arboretum & Gardens

Kentucky State Nature Preserves Commission

As a state government agency, the Kentucky State Nature Preserves Commission, works with partners both private and public to promote the use of non-invasive plant species within all government units and the public. They coordinate and lead on outreach in education to the public through workshops on invasive species identification and control; posting information on their agency web site about invasive plant ID and control. Employees attend regional symposia sponsored by the SE EPPC and also the Natural Areas Association. Seasonal staff and field staff take training on herbicide application. The agency supports a LIP staff position (Landowner Incentive Program) that has heavily favored projects based on eradication of invasive plants on private lands. The agency's preserve management staff spend ever increasing hours each year combatting the spread of invasive plants on the Commission’s 59 nature preserves and natural areas.

Kentucky Exotic Pest Plant Council

The KY EPPC encourages agency and private groups it works with to adopt the codes that best fit their group. Outreach on ID and control is done in conjunction with Master Gardener programs, local extension offices, trainings for government agencies, private non-profits and their volunteer corps. The KY EPPC has worked with the legislature to sponsor and pass legislation that will recognize the need for a comprehensive list of invasive pest species and establish a board to formally address the threat they pose, but this has not moved out of committee. The KY EPPC has developed a list of invasives for distribution as well as a booklet on how to ID and control invasive pest plants.

Lady Bird Johnson Wildflower Center

Maine Landscape and Nursery Association

Maryland Nursery and Landscape Association

The Maryland Nursery and Landscape Association, MNLA, has adopted the Voluntary Codes of Conduct. The Invasive Species committee represents the industry by attending and working as an active member of the Maryland Invasive Species Council. The Nursery trade magazine, Free State News, regularly publishes articles on topics directly related to invasive species issues. Further, the association has collaborated to present lectures and workshop sessions (perhaps list dates or event) on issues surrounding invasive species. In addition, a past president of the Maryland Nursery and Landscape Association currently serves as Secretary of the National Invasive Species Council Advisory Committee. Maryland continues to look for and aggressively pursue public awareness and education opportunities.

Massachusetts Nursery and Landscape Association, Inc

Michigan Invasive Plant Council

Michigan Nursery and Landscape Association

Mid-Atlantic Exotic Pest Plant Council

Minnesota Nursery and Landscape Association

MNLA has actively worked to educate their members about the invasive plant issue through their “Invasives Education Initiative.” Advocated by MNLA President Tim Power over the past 18 months, this initiative has included a series of articles by a wide range of green industry professionals, all with the goal of raising the awareness among members about the seriousness of the invasive plants issue.

Missouri Botanical Garden (also implementing the Codes)

The Missouri Botanical Garden revised its Living Collections Policy so that all new accessions are screened prior to planting, ensuring that no known invasives are introduced to the garden’s grounds. As part of an ongoing process, known invasive species are deaccessioned and removed from the grounds. Invasive species that are commonly planted in the region are identified in the Plantfinder database, where the general public is encouraged to use native or non-invasive alternatives.

Monrovia Growers

Montana Federation of Garden Clubs, Inc.

The Montana Federation of Garden Clubs did pass a resolution in support of this code several years ago. The group also has a dedicated invasive plant chairman focusing efforts specifically on the invasives issue throughout Montana.

Naples Botanical Garden

The Garden's Living Collections Policy, as approved by the Board of Directors, explicitly acknowledges and adheres to the Voluntary Codes of Conduct for Botanic Gardens and Arboreta. During the development of the Gardens, all plant species specified in garden plans were screened against lists of known invasive species in Florida and other similar bio-geographic areas. Known invasive species in living collections were deaccessioned and removed from the grounds. The existing living collections are regularly monitored for invasive potential. When a potentially invasive species is identified, the local invasive plant council (Florida Exotic Pest Plant Council - FLEPPC), land managers and conservation groups are notified to scout for possible escapes from local landscapes. The Garden follows all laws on importation, exportation, quarantine, and distribution of plant material across political boundaries.

All invasive species in the FLEPPC invasive plant listing are monitored and removed from natural areas. The natural areas are reviewed and treated annually for invasive exotic plant species, and a formal report generated annually. Garden staff partner with the Florida Native Plant Society to participate in Florida Department of Environmental Protection Land Management Reviews to assist in the identification and management of harmful invasive species in regional State preserves. The Garden provides continuing education opportunities to staff on current issues in invasive speceis identification and management.

The Garden also promotes native or non-invasive plant species as alternatives to invasive exotic species through education programs with the American Society of Landscape Architects, Master Gardeners, landscapers and homeowners and through partenerships with local horticultural advisory groups, including the Collier County Horticultural Advisory Team and Project Greenscape, Bayshore CRA, Radio Road East Beautification Committee.

The National Association of Exotic Pest Plant Councils

National Tropical Botanical Garden

National Tropical Botanical Garden has reviewed its living collections for potentially invasive species. As a result, NTBG removed: a number of ferns in the genus Angiopteris (one species was known to be invasive); Inga chartacea, which had invaded the garden from an outside source; and (currently being removed) Tetrastigma lanceolarium. Horticultural and groundskeeping staff have received training on the characteristics of invasiveness and are identifying other plants in the collections that are aggressive growers or those which have seeds that spread easily and rapidly. This will be an ongoing process.

NTBG’s Living Collections Policy requires that new acquisitions are screened for invasiveness.

In its preserves, NTBG continues to combat invasive species that were present prior to property acquisition or that have spread from surrounding areas, and replace these with native species. Education and outreach programs, and ecological restoration projects conducted by NTBG, or in collaboration with other organizations, agencies, nurseries, and private landowners, are increasing public awareness in Hawaii as to the need to eradicate invasives and replace with native species. Community events, public radio spots and newspaper advertisements and articles are proving quite successful.

New Jersey Nursery & Landscape Association

The New Jersey Nursery & Landscape Association adopted the codes of conduct in December of 2003 along with their own list of invasive plants which we discouraged all members to grow, specify or plant. They have been extremely successful in limiting the use of the plants on their "hit list" and were the first entity, even before the regulatory agencies to do so.

New York State Nursery and Landscape Association

North Carolina Botanical Garden (also implementing the Codes)

North Carolina Native Plant Society

The North Carolina Native Plant Society has a section on their website that provides a three tiered listing of invasive exotic plants in North Carolina. The problem of invasives was a major presentation at the 2007 NC/SC Native Plant Symposium. The NCNPS gives talks all over the state, each mentioning of the problem of invasives, which usually leads to a lengthy discussion. At their displays the group always includes invasive handouts educating the public about the problem. A number of the organization's members have participated/set up pest plant removal efforts. NCNPS has also provided nursery calling cards, patterned after MNPS's cards that allow a patron to non-confrontationally let the owner know that there is a concern.

North Creek Nurseries

North Creek Nurseries Inc. propagates and markets plants that develop the relationship between people and sustainalble outdoor environments. Our New Plant Principles for plant introductions define whether or not we grow a species or cultivar. Through extensive demonstration gardens, ecological landscapes and trialing programs, we thoroughly evaluate plants prior to intorduction. We continuously seek to identify, commercially produce and promote hardy, landscape and garden worthy plants as alternatives to invasive species. Our global collaboration with academia, arboreta, breeders, ecologists, entomologists, horticulturalists, nature societies, landscape architectcs, restoration professionals, researchers and wildlife biologists validate results. Servicing both the horticultural and ecological markets, our emphasis is on Eastern U.S. native forbs, ornamental grasses and sedges, ferns and vines. North Creek Nurseries...Where Horticulture Meets Ecology.

Ohio Nursery and Landscape Association

All of the Ohio Nursery and Landscape Association members follow all laws on importation and quarantine of plant materials across political boundaries. They work closely with the Ohio Department of Agriculture, the state regulatory agency that regulates and licenses nursery stock producers and retailers. The Association is currently working with the Ohio Invasive Plant Council in trying to determine an acceptable plant protocol for the State of Ohio. The group also has content on their consumer web site, regarding the invasives issue.

Pennsylvania Landscape and Nursery Association

Perennial Plant Association

Southeast Exotic Pest Plant Council

Southern Region, International Plant Propagators Association

The Southern Region of the International Plant Propagators Society encourages members to be cognizant of invasive plants issues in their nursery sales area and to address them responsibility. They provide educational information at annual meetings to assist in that effort. The group’s research priorities, which guide the HRI research fund, encourage development of techniques to remove invasive properties for plants.

Tampa Bay Wholesale Growers Association

The Tampa Bay Wholesale Growers was the first nursery association to endorse the Codes of Conduct and has encouraged their members to not produce plants that have been accepted as invasive in the Florida market. Their Plant Availability Locator has been amended to delete those items on the FNGLA/TBWG/FLEPPC list of plants not to grow. The group works with local and state groups to minimize impacts of mishandling plants which may have invasive properties. TBWG also works with University of Florida to provide research funds to address invasive issues and we assist scientist working on genetics to remove invasive characteristics.

Texas Nursery and Landscape Association

University of Washington (also implementing the Codes)

Washington State Nursery & Landscape Association

The Washington State Nursery & Landscape Association Board of Directors endorsed the Codes of Conduct at their October, 2006 meeting. The WSNLA has partnered with others to produce a booklet called Garden Wise that identifies several garden plants that have spread as volunteers and the booklet suggests non-invasive substitutes for gardens. Through articles in its magazine, the association has educated the professional community about the impact invasive plants have on the wild lands.

Wellesley College Botanic Gardens

Wellesley College Botanic Gardens is in the process of establishing a collections policy that deals explicitly with invasive species. The program will regularly provide educational and outreach programming about invasive species and native alternatives; help to distribute the most current (2006) Guide to Invasive Plants in Massachusetts; and remove or control invasive species from the gardens. The institution does not distribute invasive species or endorse their use in any way and is a testing site for release of organisms for biological control of invasive plants.

Wisconsin Nursery and Landscape Association

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