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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 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, and would pertain only to the sale, propagation, and intentional distribution of the plant species listed in the legislation, and not regulate the presence of the listed plants on the landscape. Unless otherwise noted, species will include all varieties and cultivars. We have also been working toward partnership with national organizations that may be able to certify ‘invasive-free’ cultivars of selected species at some point in the future.

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.

Current Status of Cease-the-Sale Bills

Click here for a summary of the Status of 2024 Missouri House and Senate Bills to Halt the Sale of Five Invasive Plants.

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

Section 1. Invasive Plant Impacts on 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.”)

Section 2. What Is the Missouri Invasive Plant Council (MoIP)?

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. 

See list of MoIP members and stakeholders.

Section 3. MoIP Rationale and Intentions for Invasive Plant List and Ceasing the Sale of Some Invasive Plants

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.

Section 4. Elements of MoIP's Idea to Cease the Sale of Some Invasive Plants

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.

Section 5. How MoIP Established Its Initial List of Invasive Plants for Review

  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.

Section 6. Instructions to Invited Reviewers of Invasive Plant List

See FAQ for a list of the invited reviewer groups.

Section 7. MoIP Process for Science-Based Input and Stakeholder Engagement
  • 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)
  • December 2020: MoIP reviewed initial feedback to determine its next steps regarding stakeholder input/comment/advisement
  • 2021 – present: Request for stakeholder input/comment/advisement

Legislative Advocacy/Engagement Phase

  • Stakeholder input will determine whether MoIP will advance to this stage or not.
Appendix A) Full MoIP-Assessed List of Invasive Plants

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
Appendix B) Further Examples of The Impacts of Invasive Plants

    Frequently Asked Questions

    Have more questions? Please email info@moinvasives.org.

    In the first phase of input, MoIP is inviting more than 90 groups to review plants for inclusion on or exclusion from a cease-the-sale list. Which groups will receive an invitation to provide feedback?
    Will you ask on the questionnaire what the total revenue of each stakeholder is so that the percentage impact can be put in perspective?
    Does MoIP have the authority to regulate invasive plants?
    Why explore legislative action in addition to educational campaigns?
    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.
    What will you do if you run into opposition?
    Do you have an idea of what plants will be on the final list for ceasing the sale?
    My organization was invited to give input on the 142 species. Will the organization's name be "attached" to any legislation that may result from the CtS idea?
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