Missouri Invasive Plant Council (MoIP) - to identify and control invasive plants

Idea to Cease the Sale of Some Invasive Plants in Missouri

This web page is for the purpose of informing interested parties of MoIP’s idea. MoIP intends for this to be a collaborative process that will take time. We welcome associate feedback.

First, MoIP defines invasive plants as “aggressive, non-native species whose presence causes or is likely to cause economic harm or environmental. These species grow and reproduce rapidly.” (Modified from Invasive.org.)

MoIP acknowledges that not all non-native plants are invasive. In fact, few are, and of the plants that are invasive, relatively few are readily available. However, plants that are invasive and are still being actively sold and distributed are concerning and limit the effectiveness of invasive-control efforts across Missouri.

Cease-the-Sale Idea

In an effort to minimize additional spread of invasive plants and to help lessen the long-term impact of existing problem species, the Missouri Invasive Plant Council (MoIP) proposes the idea of a Missouri statute that would cease the sale, propagation, and intentional distribution of some invasive plants. The proposed statute would not penalize property owners for the presence of a known invasive plant.

This would be a different statute than the existing Missouri Noxious Weed Law.

While any individual or group may propose legislation to legislators with no input from others, MoIP invites organizations with a stake in this proposal to provide thorough feedback on specific plants. We aim to maintain transparency throughout the process and desire to work with associates from many sectors, including agriculture, conservation, horticulture, academia, and utilities to find common ground on what’s best for the future of the state.

The following items document information we wish to share with approximately 90 associate groups from agriculture, horticulture, conservation, and other groups.

Rationale for an Idea to Cease the Sale of Some Invasive Plants in Missouri

Invasive plants threaten aspects of Missouri’s economy, including horticulture, agricultural production, private landowners, native plant health, native ecosystems, and the outdoor recreation industry. Many of these problematic plants are imported, bred, distributed, and promoted for sale in Missouri.

In late 2020, the Missouri Invasive Plant Task Force is seeking stakeholder input about an idea to cease the propagation, sale, and intentional distribution of some invasive plants in our state. MoIP defines “invasive” as an aggressive, non-native plant whose presence causes or is likely to cause economic harm, environmental harm, or harm to human health. This idea is different from the Missouri Noxious Weed Law. (See section 3, “MoIP Rationale and Intentions.”)
In 2015, the native plant Grow Native! Program spearheaded the Missouri Invasive Plant Task Force (MoIP), an independently organized multi-discipline group bolstering statewide efforts to identify and control the invasive plant species that severely impact native biodiversity and economies of working lands. MoIP is not a regulatory group.

The purpose of the task force is to review, discuss, and recommend educational and regulatory action related to managing known and potential non-­native invasive plant species that negatively impact natural communities and built landscapes in Missouri and elsewhere in the lower Midwest.

Representatives from the fields of conservation, agriculture, botanical science, ecological services, plant production, horticulture, landscape services and design, and arboriculture make up the task force. They communicate MoIP recommendations with their representative organizations to act as a united, supportive front. 

Private property owners, communities, farmers, business owners, industry, and tax-supported state agencies suffer economic losses controlling invasive plants. While many people are exerting effort to control invasive plants on the ground in Missouri, no state statutes exist to stop invasive plants from being sold in the state, beyond the Missouri Noxious Weed Law, which currently prohibits the sale of 12 invasive plants. As we have seen with Callery (Bradford) pear invasion, even plants thought to be sterile are exhibiting significant invasive characteristics in the field.

In an effort to stop any more invasive plant problems before they start, MoIP is proposing an idea for state legislation that would prohibit the sale, known distribution, and propagation of some invasive plants. Many states, including Indiana, Ohio, Maryland, and Tennessee have recently passed legislation of this nature, for the benefit of agricultural, horticultural, silvicultural, and other interests of their states. This proposed legislation would not penalize landowners for presence of invasive plants on their property and would not require them to control these plants.

Many Missourians are familiar with the Missouri Noxious Weed Law, which both:
  1. requires property owners to control noxious weeds on their property and 
  2. prohibits noxious weeds from being sold
Violation of either of these provisions is subject to penalty by the county prosecutor.

The state designates 12 species of weeds as noxious. Currently, adding a plant to the Noxious Weed Law list requires review and approval by the Missouri Department of Agriculture.

However, to create a new designation of plants that are banned from sale (but neither penalizes property owners for presence of invasive plants, nor requires them to treat or remove those invasive plants) would require changing statutes through the legislative process. For example, Indiana and Ohio recently enacted new state statutes and rules for invasive plants that are separate from their Noxious Weed Laws. 

MoIP's idea for a state statute is different from the Missouri Noxious Weed Law in this significant way: it would not penalize property owners for the presence of a known invasive plant. Such a statute would be complementary to—not a replacement or alteration of—the Noxious Weed Law. 
Voting Body for Inclusion of Species - MoIP recognizes the importance of carefully composing a voting body of experts to determine which species would be included on a proposed state statute limiting the sale, propagation, and intentional distribution of certain invasive plants. The legal authority in charge of implementing any statute would likely determine such a voting body. MoIP is researching compositions of voting bodies similar to those of invasive plant regulation efforts in Illinois or Ohio, both of which specifically are required to include representatives from horticulture, conservation, and academic sectors.

Restrictions - Except as provided below, it is envisioned that under such a statute, a person would not intentionally propagate, import, transfer, sell, purchase, or introduce any viable part of an invasive plant in the State. It is envisioned that these restrictions would not apply to the transfer, lease, sale, or purchase of real property on which an invasive plant is already established.

Phase-Out Periods - Some plants, particularly in the ornamental trade, require multi-year upfront investment before selling to the public. Interested stakeholder groups are invited to recommend a “phase out” period of time during which existing stock of certain invasive plant species may still be legally sold after potential passage of the statute. 

Recommendations for Trade Alternatives MoIP suggests alternative non-invasive plants with which to replace restricted invasive plants in commerce. Many alternative plants exist, including: Exemption Options - MoIP is exploring options for possible exemptions. These may include:
  • The activity is for the purpose of: 
  • Disposing of the invasive plant
  • Controlling the invasive plant
  • Using the invasive plant for research or educational purposes
  • Commercial and individual floriculture remains - properly discard so viable parts of plant don’t take root or go to seed.
Resources for the Regulating Authority - MoIP’s proposal would also authorize funding and regulatory authority to the appropriate state agency or other entity to manage the statute.

Declassification - MoIP is exploring options for possible declassification protocols.  For example, Maryland allows for declassification with this language: “A person that requests a declassification of a plant ... including cultivars of specific plants presently listed, must submit a written request to the Secretary that includes:
  • Name of the Requestor
  • Contact Information
  • Scientific name of the plant
  • Detailed justification of the request”  
Penalties and Enforcement - The legal authority in charge of implementing any statute would determine penalties and enforcement.
One of MoIP's top priorities when it formed in 2015 was to create an updated, comprehensive list of known invasive plants in Missouri. To develop this list, MoIP sought input from experienced Missouri field biologists. Twenty-six professional reviewers assigned independent ranks to 142 invasive plant species for the following three categories:
  1. Impact: How severe is the current impact of the species on natural communities in each of Missouri’s primary ecological regions?
  2. Current Abundance: Estimate the species current abundance in each of Missouri’s primary ecological regions.
  3. Trend in Distribution and Abundance: Based on observations and regional trends over the past 10 to 20 years, estimate how rapidly the species range will expand to form new occurrences throughout each of Missouri’s primary ecological regions over the next 10 years?
The results are freely available on moinvasives.org

  • Rankings are displayed through regional maps accessible as a searchable table or downloadable via Dropbox. 
  • Some species display blank maps because of insufficient review data to populate the map. The ‘insufficient data’ tag in the maps means that there were fewer than 3 reviews for that species/region. There is also a ‘no data’ tag for those without any reviews. Even though some maps show insufficient data for certain plants, they are included in the assessment list of 142 plants because they are known as invasive and/or are regulated in neighboring states.
  • Download all raw data for the Missouri Invasive Plant Assessment here (locked)
This assessment has been helpful in determining species of concern that have already established a presence in Missouri, and helps natural resource professionals plan control efforts. MoIP is inviting stakeholder groups to review this list of 142 plants as part of its process for determining a list of some invasive plants to include on a potential statue. Each plant on our list was assessed for review due to data from other regional states and inclusion on invasive.org and other reputable resources.
MoIP is inviting more than 90 groups in late 2020/early 2021 to review and provide feedback on which of the plants on the list of 142 plants they would support including on a cease-the-sale list and which ones they would oppose including on a cease-the-sale list. MoIP is providing reviewers with detailed instructions.

See FAQ for a list of the invited reviewer groups.

Science Phase

  • 2016: Research for the Missouri Invasive Plant Assessment begins compiling extensive research on known and potentially invasive plants, a process that took approximately 75 hours to complete.
  • 2017: Starting with our network of local, state and federal agencies and private industries, MoIP sought input from experienced field biologists in Missouri. MoIP received 26 completed reviews.
  • 2018: Data/metrics documented and converted into regional maps.
  • February 2019: Impact analysis/mapping shared online and in presentations, such as to the Missouri Natural Resources Conference

Stakeholder Engagement Phase

  • Winter 2019/2020: MoIP begins gathering reviewer groups/principal contact identification. MoIP begins developing documentation and input tool for review.
  • Establish composition of a review committee for review of stakeholder input
  • Spring 2020: MoIP begins develop a matrix for summarizing stakeholder input.
  • April 7, 2020: (cancelled due to COVID-19) MoIP invites stakeholders to statewide meeting on invasive plant topics
  • September 2020: introduce idea for statute to general public via a Grow Native! webinar (see recording)
  • As of early December 2020, MoIP is reviewing initial feedback to determine its next steps regarding stakeholder input/comment/advisement
  • late 2020/early 2021: Request for stakeholder input/comment/advisement

Legislative Advocacy/Engagement Phase

  • Stakeholder input will determine whether MoIP will advance to this stage or not.
This is a list of 142 species deemed to be invasive by MoIP. Their rates of invasiveness vary. To view maps associated with this ranked assessment of 142 species, click here.

MoIP is inviting approximately 90 stakeholder groups to rate these for what should be included in a proposed cease-the-sale list.

A subset of these plants are sold in farm stores, garden centers, and home improvement stores. Nearly all are available for purchase via the internet.

To re-emphasize, MoIP neither expects nor intends to prohibit sale of all these species. See Section 4 for more information on the process for adding and subtracting plants from the list.

^ Species with this symbol following their names are currently regulated under the Missouri Noxious Weed Law

*While asterix indicate plants that are currently available from traditional retail and wholesale outlets (as assessed by MoIP members associated with the horticultural trade), it is likely any of these plants can be obtained through eBay or other nonconventional retail methods.
Common Name Scientific Name Currently available from traditional retail and wholesale outlets.*
air potato Dioscorea polystachya
amur corktree Phellodendron amurense
Amur honeysuckle Lonicera maackii
Amur maple Acer tataricum Yes
Amur privet Ligustrum amurense Yes
autumn olive Elaeagnus umbellata Yes
beefsteak plant, Perilla mint Perilla frutescens Yes
bicolor lespedeza Lespedeza bicolor
birdsfoot trefoil Lotus corniculatus Yes
black swallow-wort Cynanchum louiseae
blackberry lily Belamcanda chinensis Yes
border privet Ligustrum obtusifolium Yes
Brazilian waterweed Egeria densa
brittle naiad Najas minor
bromegrass Bromus sterilis Yes
bull thistle Cirsium vulgare
burdock Arctium minus
California privet Ligustrum ovalifolium Yes
Canada thistle^ Cirsium arvense^
Caucasian bluestem Bothriochloa bladhii
cheat grass Bromus tectorum
Chinese chestnut Castanea mollissima Yes
Chinese privet Ligustrum sinense Yes
Chinese wisteria Wisteria sinensis Yes
chocolate vine Akebia quinata Yes
climbing euonymus Euonymus fortunei Yes
common buckthorn Rhamnus cathartica
common periwinkle Vinca minor Yes
common reed Phragmites australis
common tansy Tanacetum vulgare
common teasel^ Dipsacus fullonum^
crown vetch Securigera varia Yes
curly leaf pondweed Potamogeton crispus
cut-leaf teasel^ Dipsacus laciniatus^
Dahurian buckthorn Rhamnus davurica
dame's rocket Hesperis matronalis Yes
dwarf honeysuckle Lonicera xylosteum Yes
English ivy Hedera helix Yes
Eurasian watermilfoil Myriophyllum spicatum
European cranberry bush Viburnum opulus Yes
European privet Ligustrum vulgare Yes
European wand loosestrife Lythrum virgatum Yes
field bindweed^ Convolvulus arvensis^
field sowthistle Sonchus arvensis
fountain grass^ Cenchrus purpurascens^ Yes
garlic mustard Alliaria petiolata
giant hogweed Heracleum mantegazzianum
giant Miscanthus Miscanthus Yes
giant reed Arundo donax Yes
glossy buckthorn, European alder buckthorn Frangula alnus Yes
glossy privet Ligustrum lucidum Yes
golden bamboo Phyllostachys aurea Yes
golden rain tree Koelreuteria paniculata Yes
ground ivy, creeping charlie Glechoma hederacea Yes
hardheads Acroptilon repens
heavenly bamboo Nandina domestica Yes
Himalayan blackberry Rubus armeniacus
hydrilla Hydrilla verticillata
Japanese angelica tree Aralia elata Yes
Japanese barberry Berberis thunbergii Yes
Japanese chaff flower Achyranthes japonica
Japanese clover Kummerowia striata Yes
Japanese honeysuckle Lonicera japonica Yes
Japanese hops Humulus japonicus
Japanese knotweed Fallopia japonica
Japanese plume grass Miscanthus sinensis Yes
Japanese privet Ligustrum japonicum Yes
Japanese stiltgrass Microstegium vimineum
Japanese wisteria Wisteria floribunda Yes
Japanese zelkova, Japanese elm Zelkova serrata Yes
jetbead Rhodotypos scandens Yes
Johnson grass^ Sorghum halepense^
Korean clover Kummerowia stipulacea Yes
kudzu^ Pueraria montana^
Lacebark elm, Chinese elm Ulmus parvifolia Yes
leafy spurge Euphorbia esula
lesser celandine Ranunculus ficaria
mahaleb cherry Prunus mahaleb
mile-a-minute weed Persicaria perfoliata
moneywort, creeping jenny, herb twopence and twopenny grass Lysimachia nummularia Yes
Morrow's honeysuckle Lonicera morrowii
multiflora rose^ Rosa multiflora^
musk thistle^ Carduus nutans^
narrowleaf bittercress Cardamine impatiens
Norway maple Acer platanoides Yes
orange daylily, tawny daylily Hemerocallis fulva Yes
Oriental bittersweet Celastrus orbiculatus Yes
ornamental pear, callery pear Pyrus calleryana Yes
paper mulberry Broussonetia papyrifera
parrotfeather Myriophyllum aquaticum
pepperweed Lepidium latifolium
pincushion flower Scabiosa atropurpurea Yes
poison hemlock Conium maculatum
porcelain berry Ampelopsis brevipedunculata Yes
princess tree Paulownia tomentosa Yes
purple loosestrife^ Lythrum salicaria^ Yes
ravennagrass Saccharum ravennae Yes
reed canary grass Phalaris arundinacea Yes
Russian olive Elaeagnus angustifolia Yes
saltcedar Tamarix chinensis Yes
saw tooth oak Quercus acutissima Yes
Scotch thistle^ Onopordum acanthium^
sericea lespedeza Lespedeza cuneata Yes
Siberian elm Ulmus pumila Yes
silktree Albizia julibrissin Yes
silver poplar Populus alba Yes
smooth brome Bromus inermis Yes
spotted knapweed^ Centaurea stoebe^
star of Bethlehem Ornithogalum umbellatum Yes
sweet autumn virginsbower Clematis terniflora Yes
sweet breath of spring Lonicera fragrantissima Yes
tall fescue Festuca arundinacea Yes
Tartarian bush honeysuckle Lonicera tatarica
tree-of-heaven Ailanthus altissima Yes
viper's bugloss Echium vulgare Yes
water hyacinth Eichhornia crassipes Yes
waxyleaf privet Ligustrum quihoui Yes
weeping lovegrass Eragrostis curvula Yes
white mulberry Morus alba Yes
white sweet clover Melilotus albus Yes
wild parsnip Pastinaca sativa
wine raspberry Rubus phoenicolasius
winged burning bush Euonymus alatus Yes
winter vetch Vicia villosa Yes
yellow bluestem Bothriochloa ischaemum
yellow flag iris Iris pseudacorus Yes
yellow star thistle Centaurea solstitialis
yellow sweet clover Melilotus officinalis Yes
  1. See photos of escaped cultivation here.
  2. See this detailed spreadsheet of Missouri Invasive Plant Assessment for all the raw data that went into the development of the ranked assessment. Columns N through AJ show all other national, state, and regional noxious weed listings for each species.”  

Frequently Asked Questions

MoIP is inviting the following stakeholder groups in late 2020/early 2021 to provide feedback on MoIP's science-based list of 142 species. MoIP is providing them with detailed instructions.

After MoIP members review the first phase of feedback from these groups, members will revise the cease-the-sale idea. Size and stake of each organization will be considered when evaluating responses.
American Society of Landscape Architects
Association of Missouri Electric Cooperatives
Boy Scouts
Bridging the Gap
Cattlemen's Association
Conservation Federation of Missouri
Farm Service Agency
Federated Garden Clubs
Forest & Woodland Association of Missouri
Future Farmers of America
Garden Centers of America
Gateway Professional Horticultural Association
Girl Scouts - contacted through online form
Great Missouri Birding Trail
Great Rivers Greenway District
Greenhouse Growers Association
L-A-D Foundation
Landscape and Nursery Association of Greater St. Louis
Leave No Trace - contacted through online form
Lincoln Coop Extension
Magnificent Missouri
MFA Incorporated
Missouri Agribusiness Association
Missouri Agriculture Stewardship Assurance Program
Missouri Aquarium Society
Missouri Aquarium Society
Missouri Association of Counties - contacted through online form
Missouri Association of Soil & Water Conservation Districts
Missouri Beef Industry Council
Missouri Botanical Garden
Missouri Coalition for the Environment
Missouri Community Forestry Council
Missouri Consulting Foresters Association
Missouri Corn Growers Association
Missouri Cottongrower's Association
Missouri Crop Improvement Assocation
Missouri Dairy Association
Missouri Department of Conservation
Missouri Dept. of Agriculture
Missouri Dept. of Natural Resources
Missouri Energy Initiative
Missouri Farm Bureau Federation
Missouri Farmers Care
Missouri Farmers Union
Missouri Forage and Grasslands Council
Missouri Forest Products Association
Missouri Green Industry Alliance
Missouri Hemp Association
Missouri Homebuilders Association
Missouri Horse Council
Missouri Master Gardeners
Missouri Master Naturalists
Missouri Medical Cannabis Trade Association
Missouri Municipal League
Missouri Native Seed Association
Missouri Nut Growers Association
Missouri Organic Association
Missouri Park & Recreation Association
Missouri Parks Association
Missouri Pork Association
Missouri Prairie Foundation/GN
Missouri Realtors Association
Missouri Rice Council - contacted through online form
Missouri Right of Way Association
Missouri River Relief
Missouri Seedsmen’s Association
Missouri Solar Energy Industries Association
Missouri Soybean Merchandising Council
Missouri State Arboretum
Missouri State Beekeepers Association
University of Missouri Center for Agroforestry
Missouri Wine & Grape Board
Missouri Women in Agriculture
MO Environmental Education Association
MU Extension
National Forest Service
National Guard
National Park Service
National Wild Turkey Federation
Poultry Federation
Powell Gardens
Quail and Upland Wildlife Federation
Quail/Pheasants Forever
Science Teachers of Missouri
Show-Me Farm Safety
Sierra Club
St. Louis Arborists
Stream Teams United
The Nature Conservancy
TPI (turfgrowers group)
Trout Unlimited
U.S. Fish and Wildlife Service
USDA Farm Service Agency
Yes, MoIP is inviting groups to self-report the size of their membership, economic stake in invasive plants, and other considerations. Size and stake of each organization will be considered when evaluating responses. We welcome stakeholder feedback.
Since 2015 MoIP has engaged in numerous outreach opportunities promoting education on the problems, identification, control of invasive plants in Missouri. Our research has found that, while many businesses adapt to knowledge about the impact of invasive plants, some businesses continue to sell known invasive plants as long as the market demands it. This is creating undue burdens on the finances of private landowners and public agencies that spend valuable resources controlling invasive plants that continue to be sold. Stakeholder input will determine whether MoIP will advance to the legislative stage or not.
The idea to cease the sale of known invasive plants in order to slow the spread of invasive plants is by no means unique to MoIP. Any group, individual, or legislator could take up this effort independent of MoIP, and any of these entities may do so with or without inviting groups to provide input.
It is too early in the process to know what the final list will look like. The list will be shaped by the input we receive from stakeholder organizations, as well as affected individuals and businesses during the next phase of feedback.
If and when this effort results in legislation, MoIP foresees asking for a letter of support from all the organizations to present to interested legislators along with the final proposal. MoIP is not taking any input provided at this stage as defacto approval/disapproval of any later full list or other product of the CtS effort. Supportive comments and ratings now could potentially be used as support and/or justification for certain species that may end up on a final list, but those comments would be associated with the species, and not the final list in general.

Have questions? Please email [email protected]