WSR 25-10-101
PROPOSED RULES
DEPARTMENT OF AGRICULTURE
[Filed May 7, 2025, 9:05 a.m.]
Original Notice.
Preproposal statement of inquiry was filed as WSR 24-09-080.
Title of Rule and Other Identifying Information: Chapter 16-752 WAC, Noxious weed seed and plant quarantine. As a result of multiple petitions received, the department of agriculture (department) is proposing adding additional species to the noxious weed seed and plant quarantine, which would prohibit their sale and distribution. These species include: Common (English) Ivy (Hedera helix); Atlantic/Boston Ivy (Hedera hibernica); Spotted Touch Me Not (Impatiens capensis); Cape Pondweed (Aponogeton distachyos); Hanging Sedge (Carex pendula, Carex pendula subsp. pedula and Carex pendula subsp. agastachys); Green Alkenet (Pentaglottis sempervirens); Common Fennel (Foeniculum vulgare (except bulbing fennel, F. vulgare var. azoricum)); European Coltsfoot (Tussilago farfara); Herb-Robert (Geranium robertianum); Houndstongue (Cynoglossum officinale); Sulfur Cinquefoil (Potentilla recta); Wild basil/basil savory (Clinopodium vulgare); Yellow Nutsedge (Cyperus esculentus); Camelthorn (Alhagi maurorum); Russian Knapweed (Rhaponticum repens); Puncturevine (Tribulus terrestris); Rough Chervil (Chaerophyllum temulum); and Turkish Thistle (Carduus cinereus). The department proposes adding Palmer's Amaranth (Amaranthus palmeri) to the noxious weed seed and plant quarantine. The department also proposes clarifying that the Daucus carota subspecies sativus, is not included in the noxious weed seed and plant quarantine.
Hearing Location(s): On June 24, 2025, at 8:30 a.m., via Microsoft Teams conference call. Join on your computer, mobile app, or room device at https://gcc02.safelinks.protection.outlook.com/ap/t-59584e83/?url=https%3A%2F%2Fteams.microsoft.com%2Fl%2Fmeetup-join%2F19%253ameeting_YjNkYWFlMTItNWVkMi00OTcwLWFmZTEtZWFjMjQ3OWJiMThh%2540thread.v2%2F0%3Fcontext%3D%257b%2522Tid%2522%253a%252211d0e217-264e-400a-8ba0-57dcc127d72d%2522%252c%2522Oid%2522%253a%2522838c55c7-c187-44ae-8de0-2be684ce5d4a%2522%257d&data=05%7C02%7CAClow%40agr.wa.gov%7C733c7bc245bf4bacb19d08dd868f78a9%7C11d0e217264e400a8ba057dcc127d72d%7C0%7C0%7C638814672939544249%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=t4ZUjp%2F19NznRnR7fwpglY0b%2B0eoOAZNMlN2zdvQrlY%3D&reserved=0, Meeting ID 286 175 485 906 9, Passcode vt2Uz38C; or dial in by phone +1 564-999-2000,,703163236# United States, Olympia, Phone conference ID 703 163 236#.
Date of Intended Adoption: July 1, 2025.
Submit Written Comments to: Gloriann Robinson, Rules Coordinator, P.O. Box 42560, Olympia, WA 98504-2560, email wsdarulescomments@agr.wa.gov, fax 360-902-2092, by 5:00 p.m., June 24, 2025.
Assistance for Persons with Disabilities: Contact Amy Clow, plant protection rules coordinator, phone 360-902-2041, TTY 800-833-6388, email aclow@agr.wa.gov, by 5:00 p.m., June 17, 2025.
Purpose of the Proposal and Its Anticipated Effects, Including Any Changes in Existing Rules: Adding these species to the list of regulated articles in the noxious weed seed and plant quarantine helps Washington state meet the primary legislative directive set out in chapters 17.10 and 17.24 RCW, of protecting Washington's environmental and agricultural resources by using quarantines to provide a strong system for the exclusion of plant pests.
Reasons Supporting Proposal: The intrusion and spread of invasive, nonnative, weed species into Washington state continues to concern land managers, both public and private, and places economic well-being at risk for agriculture, forests, horticulture, and floriculture industries, as well as the environment and natural resources. The proposed rule amendment prevents the sale and importation of the plants listed as nursery plants and seeds. The "escape" of these plants has resulted in large public and private expenditures by landowners and land managers, weed boards, and weed districts to control. Initiating quarantines for these plants, forbidding entry or distribution of them gives a critical tool to control and prevent infestation.
The proposed quarantine prohibits the transport, buying, selling, offering for sale, or distribution of these plants, seeds, or plant parts, into or within the state of Washington, either in person or online. Businesses could no longer sell or distribute the listed plants, and the department would require the business to destroy the plants, return them to an out-of-state source, or dispose of the plants in a manner sufficient to avoid infestation.
Statutory Authority for Adoption: RCW 17.10.074, 17.24.011, and 17.24.041.
Statute Being Implemented: Chapters 17.10 and 17.24 RCW.
Rule is not necessitated by federal law, federal or state court decision.
Name of Proponent: Washington state department of ecology, Kathy Furtado, Kristi Park, Patricia Dunn, Maxine Dunkelman, Washington state noxious weed control board, and Washington State department of agriculture, governmental.
Name of Agency Personnel Responsible for Drafting, Implementation, and Enforcement: Scott Brooks, 1111 Washington Street S.E., Olympia, WA 98504, 360-485-1235.
A school district fiscal impact statement is not required under RCW 28A.305.135.
A cost-benefit analysis is not required under RCW 34.05.328. The department is not a listed agency under RCW 34.05.328 (5)(a)(i).
Scope of exemption for rule proposal from Regulatory Fairness Act requirements:
Is not exempt.
The proposed rule does impose more-than-minor costs on businesses.
Small Business Economic Impact Statement
Chapter 16-752 WAC
Noxious Weed Seed and Plant Quarantine
April 2025
SECTION 1:Describe the proposed rule, including: A brief history of the issue; an explanation of why the proposed rule is needed; and a brief description of the probable compliance requirements and the kinds of professional services that a small business is likely to need in order to comply with the proposed rule: The noxious weed and seed plant quarantine is critical in Washington state to protect its natural resources, environment, and more specifically, its agricultural, forest, horticultural, and floricultural industries. This quarantine helps to prevent the introduction and spread of invasive, nonnative plants that are highly destructive, competitive, and difficult to control. Noxious weeds can have significant economic and ecological impacts, such as threatening agriculture by reducing crop yields and affecting livestock health, harming native plant communities/biodiversity, degrading soil quality and water resources, as well as potentially impacting public health. By listing these plants in the quarantine, Washington state restricts their sale, transport, and distribution, aiming to help control them before they become widespread.
Several of the plant species under consideration to be included within WSDA's noxious weed seed and plant quarantine are both transported and sold within the state as nursery plants and seed packets. The subsequent "escape" of these plants has been a documented source of several infestations and has resulted in large public and private expenditures by landowners and land managers, weed boards, and weed districts to control.
The proposed plant species additions to the noxious weed seed and plant quarantine would create several significant implications and benefits, particularly in environmental conservation, ecosystem health, and economic cost areas. These benefits may include, but are not limited to the following:
Petitioned Species
Benefits of Prohibited Sale in Washington State
English Ivy/Variants
Environmental Conservation and Ecosystem Health
Despite its 'Class C' Noxious Weed classification in Washington state, English ivy and many of its variants are still widely available for sale. Prohibiting its sale would help reduce the spread of this invasive species, which is well known to prematurely kill trees by climbing up their trunks and taking over their canopies. This invasive ivy may also eliminate understory and habitat, adversely impacting native plants and wildlife. Should its sale be prohibited, efforts to minimize new introductions and control/remove existing ivy will be considerably more effective.
Economic Benefits
The annual economic cost of dealing with English ivy is substantial, including property damage, invasive removal costs, and habitat restoration. Prohibiting the sale of English ivy and its variants may help contribute to a reduction of these costs over time as the ivy's spread slows. There are numerous publications detailing noninvasive plant alternatives (Groundcover Alternatives for Western WA | Washington State Noxious Weed Control Board) which would allow for nurseries to sustain virtually no economic loss.
Spotted Touch Me Not
Prevents Invasion and Protects Biodiversity
Spotted Touch Me Not's aggressive spread can lead to soil erosion and habitat degradation, particularly in wetlands and riparian areas. Given its ability to displace native ecosystems by outcompeting the surrounding vegetation, this plant species is also known to create strain on wildlife that depend on these native food sources.
Prohibiting the sale of Spotted Touch Me Not will assist in the protection of wetlands and riparian areas, and by extension, the wildlife that depends on these areas.
Cape Pondweed
Prevents Invasion and Protects Waterways
Cape pondweed is an aggressively invasive plant that can outcompete native aquatic plants, disrupting ecosystems and reducing biodiversity. Its aggressive growth can clog waterways, which affects water flow and aquatic habitats.
Prohibiting the sale of Cape pondweed will assist in the protection of Washington's waterways, and by extension, the native plant and animal populations dependent on diverse, functional ecosystems.
Palmer's Amaranth
Protects Agricultural Farmland and Natural Habitats
Palmer's amaranth is highly competitive and can cause significant yield losses in crops, particularly in corn and soybeans. The weed has not only developed a resistance to multiple herbicides and is costly and difficult to control, but it also has a prolific seed production (estimated at ~250,000 seeds per plant). Its concerning adaptability and high seed production characterizes this species as a significant threat to farmland and surrounding natural habitats.
Prohibiting the sale of Palmer's amaranth will assist in the protection of Washington state's agricultural farmland/natural habitats, particularly for those that depend on corn and soybeans for their livelihood.
Hanging Sedge
Prevents Ecosystem Disruption and Protects Waterways
Hanging sedge forms dense colonies that outcompete native vegetation, reducing biodiversity in riparian and wetland ecosystems. Its growth can block stream flows, hinder fish passage, and increase erosion by destabilizing stream banks.
Prohibiting the sale of hanging sedge will not only limit its introduction into new areas (aside from its natural seed spread by water and wind), but will also assist in the protection of Washington's waterways, and by extension, the native plant and animal populations dependent on these diverse, functional ecosystems.
Green Alkanet
Prevents Invasive Spread and Protects Biodiversity
Green alkanet spreads aggressively through seeds and root fragments, outcompeting native plants and disrupting ecosystems.
The restriction of its sale will help preserve native plant species and the wildlife that depend on them, as well as minimizing the risk of ecological imbalance in forests and other shaded areas.
Common Fennel
Protects Native Ecosystems and Supports Biodiversity
Common fennel forms dense infestations, crowding out native plants critical for wildlife habitats. It also reproduces prolifically through seeds and root fragments, with seeds remaining viable in soil for years.
Prohibiting the sale of common fennel will assist in the protection of native grasslands and pollinator-friendly habitats in Washington state.
European Coltsfoot
Prevents Ecosystem Disruption
European Coltsfoot aggressively invades riparian areas and wetlands, forming dense colonies that displace native plants critical for ecosystem balance.
Protects Public Health
European Coltsfoot contains toxic pyrrolizidine alkaloids, which can cause liver damage or cancer if ingested by humans or animals.
Herb-Robert
Prevents Ecosystem Disruption
Herb-Robert invades forests and displaces native plant species, reducing biodiversity and altering habitats.
Protects Soil Health
The plant has been observed to release chemicals that inhibit the growth of other species, further harming native ecosystems.
Economic Benefits
The annual economic cost of dealing with Herb-Robert is substantial, including invasive removal costs and habitat restoration. Prohibiting the sale of Herb-Robert may help contribute to a reduction of these costs over time as the plant's spread slows.
Houndstongue
Protects Livestock
Houndstongue is toxic to cattle, horses, and other animals, causing liver damage even when consumed as a byproduct in hay.
Prevents Ecosystem Disruption
Houndstongue forms dense monocultures which displaces native plants and significantly reduces biodiversity.
Economic Benefits
The economic cost of dealing with Houndstongue is substantial, including livestock damage, invasive removal costs, and habitat restoration. Prohibiting the sale of Houndstongue may help contribute to a reduction of these costs over time as the plant's spread slows.
Sulfur Cinquefoil
Protects Native Ecosystems
Sulfur cinquefoil displaces native plants, forming dense monocultures that reduce biodiversity in grasslands, rangelands, and forests.
Preserves Forage Quality
The plant's high tannin contents make it unpalatable to livestock and wildlife, thus reducing available grazing resources.
Reduces Soil Erosion
By preventing sulfur cinquefoil's infestations, the prohibition helps maintain healthy grasslands that stabilize soil and reduce erosion.
Wild Basil/Basil Savory
Prevents Ecosystem Disruption
Wild basil forms dense monocultures, displacing native vegetation and reducing biodiversity.
Protects Native Habitats
Through restricting wild basil's sale, native plant communities and the wildlife they support are safeguarded.
Economic Benefits
Controlling wild basil's infestations can be costly and labor-intensive, requiring mechanical removal or herbicide application.
Yellow Nutsedge
Protects Agriculture and Preserves Ecosystems
Yellow nutsedge poses a significant risk to agriculture by reducing crop yields immensely. This plant species aggressively competes for water, light, nutrients, and also releases toxic chemicals to crops. Additionally, it also displaces native species in wetlands and riparian areas, thus creating natural habitat and biodiversity disruptions.
Economic Benefits
Preventing yellow nutsedge's establishment avoids expensive and labor-intensive control measures, such as repeated tillage or herbicide applications.
Camelthorn
Protects Agriculture
Camelthorn invades pastures and agricultural lands, competing with crops and forage plants while being unpalatable to livestock.
Prevents Infrastructure Damage
The plant's deep roots can grow through asphalt, concrete, and building foundations, causing costly structural damage.
Reduces Injuries and Property Damage
Camelthorn's sharp spines can harm humans, livestock, and pets.
Russian Knapweed
Protects Agriculture and Prevents Ecosystem Disruption
Russian knapweed reduces crop yields and forage quality, impacting agricultural productivity and causing financial strain. The plant species causes dense monocultures, displacing native plants, reducing biodiversity, and increasing soil erosion.
Economic Benefits
Preventing Russian knapweed's establishment avoids expensive eradication efforts involving mechanical, chemical, or biological controls.
Puncturevine
Protects Livestock and Preserves Ecosystems
Puncturevine is toxic to both sheep and cattle, causing severe health issues like paralysis and even death if consumed in mass amounts. The plant species also displaces native vegetation, reducing biodiversity and forage quality in pastures and agricultural areas.
Spread Reduction and Prevention of Injuries
Once established, the plant reproduces prolifically due to its seeds remaining viable for up to seven years. The plant also contains sharp and spiny burrs, which can injure both animals and humans.
Rough Chervil
Prevents Ecosystem Disruption and Protects Public Health
Rough chervil spreads aggressively, forming dense colonies that outcompete native plants and disrupt soil and fungal networks. Additionally, the plant is toxic to both animals and humans, causing skin irritation, gastrointestinal inflammation, cardiac weakness, and other severe symptoms if touched or ingested.
Economic Benefits
Preventing the spread of rough chervil avoids costly and labor-intensive control measures such as repeated herbicide applications and other chemical measures.
Turkish Thistle
Protects Native Ecosystems
Turkish thistle aggressively competes with native plants, reducing biodiversity and altering habitats in rangelands, meadows, and pastures.
Preserves Forage Quality and Reduces Soil Erosion
Turkish thistle diminishes available forage to livestock by outcompeting more beneficial species, which then adversely impacts agricultural productivity and causes added financial strain. By displacing native vegetation, this plant species can destabilize soil and create increased soil erosion risks to its surrounding areas.
In summary, banning the sale of all the proposed additions listed above would be a critical step forward in protecting Washington state's trees, wildlife habitats, and ecosystems, all while reducing future economic burdens associated with their inherent invasiveness.
SECTION 2:Identify which businesses are required to comply with the proposed rule using the North American Industry Classification System (NAICS) codes and what the minor cost thresholds are:
NAICS Code
(4, 5, or 6 Digit)
NAICS Business Description
Number of Businesses in Washington
Minor Cost Threshold =
1% of Average Annual Payroll
Minor Cost Threshold =
0.3% of Average Annual Revenue
Applicable Minor Cost Threshold
111421
Nursery and Tree Production
180
*$5,322.57
**$2,588.86
$5,322.57
424930
Flower; Nursery Stock; and Florists' Supplies Merchant Wholesalers
101
*$4,086.45
**$8,109.70
$8,109.70
±444220
Nursery; Garden Center; and Farm Supply Retailers
1,286
***$4,675.20
**$3,612.25
$4,675.20
*
Data source: 2021 Employment Security Department
**
Data source: 2021 Department of Revenue
***
Data source: 2021 Quarterly Census of Employment and Wages (Bureau of Labor Statistics)
±
Data source: Census.gov 2017 report. NAICS code 444240 was created in 2022 to better reflect primary activity of retailing nursery, garden products, and farm supplies
SECTION 3:Analyze the probable cost of compliance. Identify the probable costs to comply with the proposed rule, including: Cost of equipment, supplies, labor, professional services, and increased administrative costs; and whether compliance with the proposed rule will cause businesses to lose sales or revenue: Complying with the proposed additions to WSDA's noxious weed seed and plant quarantine may incur several types of costs for nurseries and tree producers, florists, garden centers, landscapers, and merchant wholesalers. Below are a few of the identified considerations and potential minimal costs for industry:
Compliance with Regulations (General): Businesses will need to ensure all aspects of the business comply with the new regulations, including no longer sourcing, disposing of, and stopping sales of prohibited plants. These ongoing requirements may require administrative effort, but are estimated to have a very minimal impact and may include, but are not limited to, some of the following:
•Removing prohibited plants from inventory/database and properly disposing of them;
•No longer ordering prohibited plants with the intent to sell; and
•Educating employees on the new additions to the quarantine list.
Inventory Management and Disposal: Should any of the impacted businesses, such as nurseries or garden centers, be found to have prohibited plants in their inventory, they may need to dispose of these plants which could result in direct financial losses. Additionally, there may also be costs associated with replacing disposed of plants with compliant species, thus creating additional need and/or time for inventory management. As it relates to inventory management and disposal, businesses may come to expect the following costs:
•Identification and Segregation: Businesses may need to audit their inventory, as well as identify and remove plants and plant parts that are now prohibited. Depending on the number of plants that need to be removed from inventory, this process may increase labor costs for a brief amount of time.
•Disposal Costs: Plants that are identified as prohibited may need to be disposed of in a manner compliant with regulations which can include specialized disposal methods or facilities (i.e., double bagging and placing into municipal waste or burning, if allowed). While these costs can be significant for businesses, these means of disposal are standard practice and should already be implemented by industry.
•Inventory Adjustments: Businesses may need to adjust their inventory management systems to ensure newly quarantined plants and plant parts are not ordered, inventoried, or sold. This may include updating software, training staff, and potentially writing off inventory that cannot be sold.
oAdditionally, should a business identify that a newly added prohibited plant species was profitable, they may opt to incur additional expenses to build out their inventory with alternatives published within Washington state noxious weed control board's noninvasive plant alternatives.
Additional Employee Time: Nurseries, dealers, and the like may expect to incur additional employee time costs as a result of complying with the newly updated noxious weed seed and plant quarantine list. These costs may include one or more of the following:
•Training and Education: While not required, businesses may have operational framework requiring employees to be trained to recognize and handle the newly added prohibited plant species. As a result, this includes both time and potentially external training costs associated with these efforts and/or becoming familiar with Washington state noxious weed control board's noninvasive plant alternatives publications.
•Customer Education: Businesses may find an increased need to educate their customers about the changes ensuring they are aware of the new regulations and that some previously available plant species are now unavailable.
WSDA employed a survey approach to ensure that stakeholder feedback regarding the proposal, along with their perceived economic impact data, were systematically collected and analyzed. These surveys aimed to capture feedback by requesting nominal data detailing the costs of compliance but also offered opportunities for fill-in/narrative responses.
The survey was sent out to a total of 4,000 recipients as part of WSDA's plant services program's newsletter with an open response period of six weeks. Ninety-two responses were received.
Below are the questions and responses received:
Table 3.1
Question Detail
Responses
Question #1: Is your business small (0-50 employees) or large (50+ employees)?
Small (0-50 employees): 89
Large (50+ employees): 3
Table 3.2
Question Detail
Responses
Question #2: What area of specialization best describes your business?
Gardening and Propagation: 66
Decorative Uses: 20
Medicinal Uses: 2
Culinary Uses: 4
Table 3.3
Question Detail
Responses
Question #3: Does your business sell any of the following plants as whole, parts, or seeds?
If yes, please specify which, its estimated yearly revenue, and its estimated percentage of your total annual sales.
If no, please indicate "N/A."
(1) Common English Ivy (Hedera helix) including "Baltica," "Pittsburgh," "Star," "Hahns," and "Gold Child" varieties.
(2) Atlantic/Boston Ivy (Hedera hibernica) including "Hibernica" variety.
(3) Spotted Touch Me Not (Impatiens Capensis)
(4) Cape Pondweed (Aponogeton distachyos)
(5) Palmer's Amaranth (Amaranthus palmeri)
Eighty-five respondents answered "N/A" or some variation of "None." Information about the seven respondents that do sell one of these five species can be found below:
Respondent #
Plant Species
Estimated Total Annual Sales
16 (small)
Common English Ivy
$50 - $80 yearly
17 (small)
Ornamental Ivy, only variegated forms
Not provided
20 (small)
Common English Ivy and Atlantic/Boston Ivy
$200 yearly
44 (small)
Common English Ivy and Atlantic/Boston Ivy
Not provided
84 (small)
Not provided
$150 yearly
93 (small)
Common English Ivy
About $2,000 yearly. Less than 1% of total annual sales
94 (small)
Common English Ivy
About $2,300 yearly and 0.5% of total annual sales
Table 3.4
Question Detail
Responses
Question #4: Does your business sell any of the following plants as whole, parts, or seeds?
If yes, please specify which, its estimated yearly revenue, and its estimated percentage of your total annual sales.
If no, please indicate "N/A."
(1) Hanging Sedge (Carex pendula and subsp., and Carex pendula subsp. agastachys)
(2)Green Alkenet (Pentaglottis sempervirens)
(3) Common Fennel (Foeniculum vulgare)except bulbing fennel and F. vulgare var. azoricum.
(4) European Coltsfoot (Tussilago farfara)
(5) Herb-Robert (Geranium robertianum)
Eighty-nine respondents answered "N/A" or some variation of "None." Information about the three respondents that do sell one of these five species can be found below:
Respondent #
Plant Species
Estimated Total Annual Sales
10 (small)
Common Fennel
$50 yearly
*80 (small)
*Common fennel and European Coltsfoot
*Not provided
88 (small)
Common Fennel
~$100 yearly
*Additional Provided Information
Respondent #80: Common Fennel is a very popular culinary spice and the bulb is eaten. It is widely cultivated in our agricultural area. Coltsfoot is a well utilized herbal medicinal and is greatly helpful in teas and tinctures. Both are in our tea blends, and we sell them individually. Because we have so many herbs we sell, the percentage of sales is small in comparison to the overall income, however these are both extremely important plants.
WSDA Response: The quarantine will not regulate denatured fennel seeds. Additionally, the main difference between common fennel and bulbing fennel is that common fennel is grown for its leaves and seeds, while bulbing fennel is grown for its bulb-like base and culinary uses:
Common fennel (to be quarantined) - Also known as sweet or bronze fennel, this herb-like variety is grown for its leaves, seeds, and shoots, which can be used to flavor soups, salads, and seafood. Common fennel can grow up to 7 ft tall and has a licorice scent. It's a prolific self-seeder and can become invasive.
Bulbing fennel (NOT to be quarantined) - Also known as Florence fennel or finocchio, this vegetable-like variety is grown for its bulb-like base, which is eaten as a vegetable. The bulb is harvested before the plant flowers or sets seed. Florence fennel can grow up to 5 ft tall and has a bulb base, fronds, and seeds.
While these restrictions may affect herbal teas, tinctures, or medicines made from prohibited plants, the quarantine aims to prohibit the sale, distribution, and transportation of plants, plant parts, and seeds as opposed to its processed product counterparts.
Table 3.5
Question Detail
Responses
Question #5: Does your business sell any of the following plants as whole, parts, or seeds?
If yes, please specify which, its estimated yearly revenue, and its estimated percentage of your total annual sales.
If no, please indicate "N/A."
(1) Houndstongue (Cynoglossum officinale)
(2) Sulfur Cinquefoil (Potentilla recta)
(3) Wild Basil/Basil Savory (Clinopodium vulgare)
(4) Yellow Nutsedge (Cyperus esculentus)
(5) Camelthorn (Alhagi Maurorum)
All 92 respondents answered "N/A" or some variation of "None."
Table 3.6
Question Detail
Responses
Question #7: Does your business sell any of the following plants as whole, parts, or seeds?
If yes, please specify which, its estimated yearly revenue, and its estimated percentage of your total annual sales.
If no, please indicate "N/A."
(1) Russian Knapweed (Rhaponticum repens)
(2) Puncturevine (Tribulus terrestris)
(3) Rough Chervil (Chaerophyllum temulum)
(4) Turkish Thistle (Carduus cinereus)
All 92 respondents answered "N/A" or some variation of "None."
Table 3.7
Question Detail
Responses
Question #7: If your business sells any of the plants considered for quarantine from above, what percentage of inventory do they represent?
0-25%: 13
26-50%: 1
51-75%: 0
76-100%: 0
We don't have/sell any: 78
The following table demonstrates common compliance cost areas for businesses affected by invasive plant regulations, with example cost ranges based on both the survey responses and available industry data/typical business practices. Actual costs will vary by business size and inventory:
Cost Area
One-Time Cost Estimate
Annual Cost Estimate
Notes/Examples
Inventory Audit and Removal
$500 - $2,500
N/A
Labor to review stock, identify, and remove prohibited species.
Disposal of Prohibited Inventory
$250 - $2,000
N/A
Includes safe disposal/transport for unsellable plants.
System/Process Updates
$300 - $1,000
$100 - $300
Updating sales, inventory, and ordering systems to flag prohibited species.
Staff Training
$250 - $1,500 (initial)
$200 - $500 (Refresher/Turnover)
External training courses or in-house sessions for plant ID and compliance.
Professional Services (Consultants)
$500 - $2,000 (as needed)
N/A
Plant identification, legal, or compliance consulting.
Customer Education
$200 - $500
$100 - $250
Printing signage, handouts, or website updates to explain the changes.
Lost Revenue—Unsellable Stock
Variable
N/A
Depends on quantity/value of prohibited plants in inventory.
Additional Considerations:
• One-time costs are typically incurred during the initial compliance period (first year).
• Annual costs reflect ongoing needs, such as staff turnover, periodic audits, or customer outreach.
• Training rates are based on industry pricing for invasive species management courses and consulting.
   See: Invasive Plant Control, Inc.
• Disposal and lost revenue can vary widely depending on business inventory and the number of prohibited species held.
SECTION 4:Analyze whether the proposed rule may impose more-than-minor costs on businesses in the industry: In Washington state, if a proposed rule is expected to impose more than "minor costs" on businesses, it triggers the requirement for completing a small business economic impact statement. As defined in chapter 19.85 RCW: Regulatory Fairness Act, a "minor cost" is the cost per business that is less than three-tenths of one percent of a business's annual revenue or $100, whichever is greater, or one percent of annual payroll.
As previously detailed within Section 2 of this analysis, WSDA anticipates the proposed rule amendments to impact businesses operating under the following industry codes:
•NAICS 111421: Nursery and Tree Production.
•NAICS 424930: Flower; Nursery Stock; and Florists' Supplies Merchant Wholesalers.
•NAICS 444220: Nursery; Garden Center; and Farm Supply Retailers.
While the WSDA industry survey did not inquire as to the participants' NAICS code, the table below provides a "Minor Cost Threshold" analysis and matrix which consider the respondents' perceived cost and/or loss of revenue for compliance in relation to all potentially applicable NAICS codes.
Business
Business Size
NAICS Codes
Perceived Cost/Loss of Revenue for Compliance
Minor Cost Threshold
Conclusion
10
Small
Not Provided
$50/year
$5,322.57 if operating under NAICS code 111421.
Business #10 estimates an annual loss of revenue amounting to $50/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
16
Small
Not Provided
$50-$80/year
$5,322.57 if operating under NAICS code 111421.
Business #84 estimates an annual loss of revenue amounting to $50-$80/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
17
Small
Not Provided
Not Provided
$5,322.57 if operating under NAICS code 111421.
Without data detailing the perceived annual cost/loss of revenue for compliance, it is inconclusive as to whether the proposed rule would impose more-than-minor costs on business #17.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
44
Small
Not Provided
Not Provided
$5,322.57 if operating under NAICS code 111421.
Without data detailing the perceived annual cost/loss of revenue for compliance, it is inconclusive as to whether the proposed rule would impose more-than-minor costs on business #44.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
80
Small
Not Provided
Not Provided
$5,322.57 if operating under NAICS code 111421.
Without data detailing the perceived annual cost/loss of revenue for compliance, it is inconclusive as to whether the proposed rule would impose more-than-minor costs on business #80.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
84
Small
Not Provided
$150/year
$5,322.57 if operating under NAICS code 111421.
Business #84 estimates an annual loss of revenue amounting to $150/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
88
Small
Not Provided
$100/year
$5,322.57 if operating under NAICS code 111421.
Business #88 estimates an annual loss of revenue amounting to $100/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
93
Small
Not Provided
$2,000/year
$5,322.57 if operating under NAICS code 111421.
Business #93 estimates an annual loss of revenue amounting to $2,000/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
94
Small
Not Provided
$2,300/year
$5,322.57 if operating under NAICS code 111421.
Business #84 estimates an annual loss of revenue amounting to $2,300/year, which is less-than-the-minor cost thresholds of NAICS codes 111421, 424930, and 444220. Thus, it can be concluded that this business would not have more-than-minor costs imposed on them.
$8,109.70 if operating under NAICS code 424930.
$4,675.20 if operating under NAICS code 444220.
All three of the large business survey participants responded that they do not sell any of the proposed plant species to be prohibited. The remaining 80 (small) business survey participants responded similarly in that they do not sell any of the soon-to-be prohibited plant species, or that their inventory and sales were considered very minor aspects of their operations.
Even in scenarios where a business experiences compliance costs at the higher end of the estimated ranges, for example, incurring several thousand dollars in one-time expenses for inventory removal, system updates, staff training, and lost inventory, the likelihood of these costs exceeding the industries' minor cost thresholds is extremely low. While some businesses may face higher initial compliance expenses, these costs are not expected to approach a level that would create a significant financial burden or threaten business viability.
Conversely, businesses that are less prepared or slower to adjust may face higher costs, particularly if they need to dispose of significant unsellable inventory or invest in outside expertise. However, even at the upper end of the estimated cost range, these expenses are generally expected to remain well below the industry's minor cost thresholds, meaning that the overall financial impact should remain manageable for most businesses.
SECTION 5:Determine whether the proposed rule may have a disproportionate impact on small businesses as compared to the 10 percent of businesses that are the largest businesses required to comply with the proposed rule: RCW 19.85.040(1) requires WSDA to compare the cost of compliance for small businesses with the cost of compliance for the 10 percent of businesses that are the largest businesses required to comply with the proposed rules using one or more of the following as a basis for comparing costs: (a) Cost per employee; (b) cost per hour of labor; or (c) cost per $100 of sales.
The addition of plant species to WSDA's noxious weed seed and plant quarantine may have a disproportionate impact on small businesses, particularly those in the nursery, horticulture, and landscaping industries. WSDA has determined that the following subject areas would need to be considered to accurately assess whether the impact(s) are disproportionate:
(1) Impact on Sales and Inventory: Small businesses that rely on selling plants, seeds, or nursery products may experience significant losses if they are forced to remove certain species from their inventory. This may be challenging for smaller operations that do not have the resources to quickly adapt to new regulations or find alternative products to replace the newly prohibited ones.
(2) Compliance and Regulatory Burden: Small businesses may struggle more than larger counterparts to comply with new regulations due to limited expertise and/or resources. The need to identify and remove quarantined species, as well as to ensure that all products comply with new rules, can be time-consuming and costly. Thus, it is possible that the compliance and regulatory burden expense area is disproportionately heavy on smaller businesses.
(3) Economic Impact: The prohibition of selling and distributing certain plant species may lead to economic hardships or losses for small businesses, especially if any of the soon-to-be added plants are significant contributors to their revenue. Thus, it is possible that this may lead to job losses, reduced employee hours, or even business closures if the impact is severe enough.
(4) Voluntary Compliance and Public Pressure: While some small businesses may voluntarily stop selling invasive species in response to public pressure or educational/advocacy campaigns, others may find it increasingly difficult to do so without clear regulatory mandates. Voluntary compliance, however, can still pose challenges for small businesses that need to find, compile, and market noninvasive alternative products.
To better understand the potential financial impacts and operational changes that this proposed rule adoption may have on the industry, WSDA sought to obtain survey responses from over 4,000 recipients within the plant services' nursery subscriber list. Despite efforts to gather representative economic impact data from both small and large businesses, WSDA found the overall participation skewed heavily toward small businesses through its survey responses and webinar attendance. Additionally, for the few large businesses that did participate in the survey, those participants opted to provide narrative responses over nominal amounts.
Without any nominal data/confirmation of prohibited plant sales provided by large businesses or enough responses to indicate 10 percent of businesses that are the largest businesses required to comply with the proposed rule, WSDA determined that the rule has an inherently disproportionate impact on small businesses.
SECTION 6:If the proposed rule has a disproportionate impact on small businesses, identify the steps taken to reduce the costs of the rule on small businesses. If the costs cannot be reduced provide a clear explanation of why: After review and careful consideration, WSDA was unable to offer some of the mitigation methods detailed below as the proposed rule is intended to protect Washington state's natural resources, environment, and more specifically, its agricultural, forest, horticultural, and floricultural industries.
RCW 19.85.030(2) requires consideration of the following methods of reducing the impact of the proposed amendment on small businesses:
(a) Reducing, modifying, or eliminating substantive regulatory requirements: The purpose of adding these plant species to the noxious weed seed and plant quarantine is to protect Washington state's natural resources, environment, and more specifically, its agricultural, forestry, horticultural, and floricultural industries. Reducing, modifying, or eliminating the substantive regulatory requirements of this rule is counterproductive to the purpose of the rule itself and places Washington state at risk. As such, this mitigation method is not feasible for WSDA to offer.
(b) Simplifying, reducing, or eliminating recordkeeping and reporting requirements: The addition of plant species to the noxious weed seed and plant quarantine does not impose any recordkeeping or reporting requirements. As such, this mitigation method is beyond the proposed rule amendment's scope.
(c) Reducing the frequency of inspections: The addition of plant species to the noxious weed seed and plant quarantine does not present WSDA any opportunities to reduce the frequency of inspections. As such, this mitigation method is beyond the proposed rule amendment's scope.
(d) Delaying compliance timetables: The addition of plant species to the noxious weed seed and plant quarantine does not present WSDA any opportunities to delay compliance timetables. As such, this mitigation method is beyond the proposed rule amendment's scope.
(e) Reducing or modifying fine schedules for noncompliance: The addition of plant species to chapter 16-752 WAC, Noxious weed seed and plant quarantine, does not present WSDA any opportunities to reduce or modify fine schedules for noncompliance. As such, this mitigation method is beyond the proposed rule amendment's scope.
(f) Any other mitigation techniques including those suggested by small businesses or small business advocates:
Previously Petitioned Species Asked to be Removed from Consideration
• Creeping Charlie (Glechoma hederacea)
• Creeping Jenny (Lysimachia nummularia)
• Periwinkle (Vinca minor)
Mitigation Comment/Suggestion #1
Re: Creeping Charlie, Creeping Jenny, Periwinkle
Submitted by: Raintree Nursery, Nursery Advisory Committee Member
I feel like it is not our job to determine which plants are noxious weeds within our state. If we recommend to stop sales of plants because they might be added to the noxious weeds list at some point then we are making the determination that they are a problem. Recommending that sales of plants that are ON the state noxious weed list be stopped makes total sense. Are any of these plants on any county noxious weed lists? Even if they were, it might be difficult to make a rule about selling plants at the county level.
Perhaps nurseries that sell these plants could be required to provide information to the customer about how these plants grow, and what might be required if/when they begin to spread out of their intended space.
Mitigation Comment/Suggestion #2
Re: Creeping Charlie, Creeping Jenny, Periwinkle
Submitted by: Briggs Nursery, Nursery Advisory Committee Member
[Creeping Charlie] I am not familiar enough to make a comment either way on this plant.
[Creeping Jenny] I have no objection if this is being added to the list.
[Periwinkle (Vinca minor)] should not be on the list… there are plenty of better choices, however, it does not warrant enough of a threat in Washington to be added to the list (in my opinion).
Mitigation Comment/Suggestion #3
Re: Creeping Charlie, Creeping Jenny, Periwinkle
Submitted by: WSNLA Executive Director, Nursery Advisory Committee Member
[Retail Perspective] Where does it end? I can see the invasiveness, but I could count on and on and on and on again the number of plants that could be viewed as such. I totally agree education is the key. We sell all these plants, but not as any kind of recommended landscape staple ground over, but rather as basket stuffers for container gardens. I would say 99% of customers do just that, use it to spill out of pots for interest. We do stock Blue Vinca in our ground over area, but don't sell a ton. To me the problem with Vincais commercial use, not as much homeowner use. It has been over planted by the millions in parks, medians, parking lots, vacant slopes, condos, apartments and other commercial properties all over for decades. Get these folks who design or install to quit recommending it and offer substitute.
We choose to educate our staff on such things, and it certainly comes up with customers if they ask. Again education, if we can let the public know and caution them about choices, I think vast majority will make the right decisions.
[Landscape Design Perspective] My opinion, all 3 of the plants listed should be moved from the monitor list and moved to one of the classes of noxious weeds AND education at nurseries should be offered for all classes of noxious weeds.
[Landscape Perspective] I agree with the other, "current input that was provided to WSDA", etc. That the hierarchy of the plants already being monitored by the board should be the plants considered for moving up the list. These 3 specific plants in my opinion should not just jump up the ladder of invasives.
I agree our industry should do more on educating consumers on many plants. Plenty of ground covering plants and vines get way out of control. I don't know this as fact, but will assume that in their consideration for listing the degree of difficulty in their eradication is an important factor.
WSDA Response: The petitions to add these particular species came from a citizen, but we are still obligated to consider them. [The Department] agrees that the rationale for adding a prohibited plant is better when the plant is already on the noxious weed list. Either way, we always want to seek input from NAC (Nursery Advisory Committee) members on plants that are actively being sold in the nursery trade before coming to a decision. Your suggestion to educate customers about the potential invasiveness of these species is a good one and might be a better solution.
Thanks for the input. We've decided against adding these species to the list, for the time being. There would need to be stronger justification, including actual status as a noxious weed at the state level.
SECTION 7:Describe how small businesses were involved in the development of the proposed rule: In Washington state, the efforts to prohibit the sale of English ivy, amongst others in the proposed rule, have been largely driven by advocacy groups, community initiatives, and regulatory bodies rather than small businesses themselves.
Advocacy and Community Efforts: Groups like the Whatcom Million Trees Project and the Edmonds Ivy League have actively been campaigning to stop the sale of English ivy and have petitioned WSDA to add it to its noxious weed seed and plant quarantine, boasting an estimated 950+ signatures in support. These organizations have been educating the public, persuading local nurseries to stop selling English ivy, and advocating for its inclusion in chapter 16-752 WAC.
Public Awareness and Education: The Whatcom Million Trees Project is raising awareness among both public and private landowners about the dangers of English ivy, encouraging to remove it from their trees and properties. These efforts have included community engagement and volunteer work parties which ultimately led to the creation/submission of the stop sale petition to WSDA.
Collaboration with Nurseries: Efforts are being made to convince local nurseries to voluntarily stop selling English ivy. Some local nurseries have agreed to stop selling English ivy in response to advocacy efforts and community pressures, while others are still being persuaded. For example, nurseries like Garden Spot Nursery, Serenity Farm & Garden, and Tuxedo Garden have all committed to no longer selling English ivy. Additionally, consumers are encouraged to support nurseries that have stopped selling ivy and instead offer noninvasive alternatives.
SECTION 8:Identify the estimated number of jobs that will be created or lost as the result of compliance with the proposed rule: The addition of plant species to chapter 16-752 WAC may have both positive and negative impacts on employment, depending on the specific sectors affected.
In support of the notion that the proposed list of plant species to be added to the noxious weed seed and plant quarantine may create jobs, WSDA has identified the following area:
(1) Education and Outreach: By preventing the spread of invasive species through restricting their sale and delivery in Washington state, there may be an increased need for educators and outreach specialists to inform the public about the risks of allowing the establishment of invasive species, as well as both the importance and availability of noninvasive alternatives. As protecting agriculture and forestry remains an important initiative of the state, the need for educational specialists can be critical at the business, city, county, or state level.
In support of the prospect that the addition of the proposed plant species to the noxious weed seed and plant quarantine may eliminate jobs, WSDA has identified the following areas:
(2) Nursery and Horticulture Industry: WSDA's prohibition of sale and distribution of plant species in chapter 16-752 WAC may lead to loss of jobs in nurseries, garden centers, and landscaping businesses that previously sold these plants. As a result, these businesses may need to adjust their product offerings which could result in one or more of the following:
1. Reduced market share for the business if one of their mainstay products is added;
2. Reduced demand for certain job position(s) that are heavily associated with soon-to-be quarantined plants; and
3. Business closure if unable to adjust to new regulations.
(3) Seed and Plant Distribution: Companies that are now regulated on the distribution side of seeds and plants may also potentially experience loss of jobs as their product lines are restricted.
In sum, the proposed rule may either create additional jobs or cause a loss of jobs depending on a business's adaptability within the industry.
A copy of the statement may be obtained by contacting Gloriann Robinson, Rules Coordinator, P.O. Box 42560, Olympia, WA 98504-2560, phone 360-902-1802, fax 360-902-2092, TTY 800-833-6388, email wsdarulescomments@agr.wa.gov.
May 6, 2025
Greg Haubrich
Assistant Director
RDS-6236.2
AMENDATORY SECTION(Amending WSR 21-05-019, filed 2/8/21, effective 3/11/21)
WAC 16-752-610Regulated articles.
All plants, plant parts, and seeds in packets, blends, and "wildflower mixes" of the following listed species are designated as regulated articles under the terms of this noxious weed seed and plant quarantine. This list is comprised of the most recent and accepted scientific and common names of the quarantine plant species. Regulated status also applies to all synonyms of these botanical names and interspecies hybrids if both parents are regulated species:
Scientific Name
Common Names
Abutilon theophrasti
velvetleaf
Ailanthus altissima
tree-of-heaven
Alhagi maurorum
camelthorn
Alliaria petiolata
garlic mustard
Amaranthus palmeri
Palmer's amaranth
Amorpha fruticosa
indigobush, lead plant
Anchusa officinalis
common bugloss, alkanet, anchusa
Anthriscus sylvestris
wild chervil
Aponogeton distachyos
cape pondweed
Arum italicum
Italian arum
Arundo donax (except variegated cultivars)
giant reed
Bassia scoparia (syn. Kochia scoparia)
kochia, summer-cyprus, burning-bush, fireball, Mexican fireweed
Berteroa incana
hoary alyssum
Brachypodium sylvaticum
false brome
Buddleia davidii (except accepted sterile cultivars)
butterfly bush
Butomus umbellatus
flowering rush
Cabomba caroliniana
fanwort
Carduus acanthoides
plumeless thistle
Carduus cinereus
Turkish thistle
Carduus nutans
musk thistle, nodding thistle
Carduus pycnocephalus
Italian thistle
Carduus tenuiflorus
slenderflower thistle
Carex pendula, Carex pendula subsp. pedula and Carex pendula subsp. Agastachys
hanging sedge
Centaurea calcitrapa
purple starthistle
Centaurea diffusa
diffuse knapweed
Centaurea jacea
brown knapweed, rayed knapweed, brown centaury horse-knobs, hardheads
Centaurea macrocephala
bighead knapweed
Centaurea nigra
black knapweed
Centaurea nigrescens
Vochin knapweed
Centaurea stoebe
spotted knapweed
Centaurea x gerstlaueri (syn. Centaurea jacea x nigra)
meadow knapweed
Chaenorhinum minus
dwarf snapdragon
Chaerophyllum temulum
rough chervil
Clematis orientalis
oriental clematis
Clinopodium vulgare
wild basil/basil savory
Conium maculatum
poison hemlock
Crassula helmsii
Australian swamp stonecrop
Crupina vulgaris
common crupina
Cynoglossum officinale
houndstongue
Cyperus esculentus
yellow nutsedge
Cyperus rotundus
purple nutsedge
Cytisus scoparius
Scotch broom
Daphne laureola
spurge laurel
Daucus carota(except for subsp. sativus)
wild carrot, Queen Anne's lace
Echium vulgare
blueweed, blue thistle, blue devil, viper's bugloss, snake flower
Egeria densa
Brazilian elodea
Epilobium hirsutum
hairy willow herb
Euphorbia myrsinites
myrtle spurge
Euphorbia oblongata
eggleaf spurge
Euphorbia virgate (syn. Euphorbia esula)
leafy spurge
Fallopia japonica
Japanese knotweed
Fallopia sachalinensis
giant knotweed
Fallopia x bohemica
Bohemian knotweed
Ficaria verna
lesser celandine
Foeniculum vulgare (except bulbing fennel, F. vulgare var. azoricum)
common fennel
Galega officinalis
goatsrue
Genista monspessulana
French broom
Geranium lucidum
shiny geranium
Geranium robertianum
herb-Robert
Glossostigma diandrum
mud mat
Glyceria maxima
reed sweetgrass, tall manna grass
Gymnocoronis spilanthoides
Senegal tea plant
Hedera helix
common (English) ivy
Hedera hibernica
Atlantic/Boston ivy
Helianthus ciliaris
Texas blueweed
Heracleum mantegazzianum
giant hogweed, giant cow parsnip
Hibiscus trionum
Venice mallow, flower-of-an-hour, bladder ketmia, modesty, shoo-fly
Hieracium spp. All nonnative species and hybrids
nonnative hawkweeds
Hydrilla verticillata
hydrilla
Hydrocharis morsus-ranae
European frog-bit
Impatiens capensis
spotted touch-me-not
Impatiens glandulifera
policeman's helmet
Impatiens parviflora
small-flowered jewelweed
Iris pseudacorus
yellow flag iris
Isatis tinctoria
dyers' woad
Jacobaea vulgaris (syn. Senecio jacobaea)
tansy ragwort
Lagarosiphon major
African elodea
Lamiastrum galeobdolon
yellow archangel
Lepidium latifolium
perennial pepperweed
Leucanthemum vulgare
oxeye daisy, white daisy, whiteweed, field daisy, marguerite, poorland flower
Limnobium laevigatum
South American spongeplant
Limnobium spongia
American spongeplant
Linaria dalmatica spp. dalmatica
Dalmatian toadflax
Ludwigia hexapetala
water primrose
Ludwigia peploides
floating primrose-willow
Lycopsis arvensis
annual bugloss
Lysimachia vulgaris
garden loosestrife
Lythrum salicaria
purple loosestrife
Lythrum virgatum
wand loosestrife
Marsilea mutica
Australian water clover
Mirabilis nyctaginea
wild four o'clock, umbrella-wort
Murdannia keisak
marsh dew flower, Asian spiderwort
Myriophyllum aquaticum
parrotfeather
Myriophyllum heterophyllum
variable-leaf milfoil
Myriophyllum spicatum
Eurasian watermilfoil
Najas minor
slender-leaved naiad, brittle naiad
Nymphoides peltata
yellow floating heart
Onopordum acanthium
Scotch thistle
Pentaglottis sempervirens
green alkenet
Persicaria wallichii (syn. Polygonum polystachyum)
Himalayan knotweed
Potentilla recta
sulfur cinquefoil
Proboscidea louisianica
unicorn-plant
Pueraria montana var. lobata
kudzu
Rhaponticum repens
Russian knapweed
Sagittaria graminea
grass-leaved arrowhead
Sagittaria platyphylla
delta arrowhead
Salvia aethiopis
Mediterranean sage
Salvia pratensis
meadow clary
Salvia sclarea
clary sage
Schoenoplectus mucronatus
ricefield bulrush
Silybum marianum
milk thistle
Solanum elaeagnifolium
silverleaf nightshade
Solanum rostratum
buffaloburr
Soliva sessilis
lawnweed
Sorghum halepense
johnsongrass
Spartina alterniflora
smooth cordgrass
Spartina anglica
common cordgrass
Spartina densiflora
dense-flowered cordgrass
Spartina patens
salt meadow cordgrass
Spartium junceum
Spanish broom
Stratiotes aloides
water soldier
Tamarix ramosissima
saltcedar
Thymelaea passerina
spurge flax
Torilis arvensis
hedgeparsley
Trapa natans
water chestnut, bull nut
Trapa bicornus
water caltrap, devil's pod, bat nut
Tribulus terrestris
puncturevine
Tripidium ravennae
Ravenna grass
Tussilago farfara
European coltsfoot
Ulex europaeus
gorse, furze
Utricularia inflata
swollen bladderwort
Zygophyllum fabago
Syrian bean-caper