Known for its habit of growing up and over 100 ft+ trees and structures, creating carpeted growths in the forest, and housing allergens and rodents, it’s no mystery to PNW locals that common ivy (Hedera helix, AKA English ivy) is an impactful plant. Ivy has been classified as a noxious weed in Washington state since 2002, yet until last month (August, 2025) it could be sold and purchased with no legal implications.
So why did it take 23 years to ban common ivy from the market? Let’s get into the weeds (pun absolutely intended).
What the state law says
Invasive plants in Washington state may be legally regulated in two ways. That is, if they must be controlled (designated Noxious Weeds) and if they can be sold/bought (Prohibited Plants). These regulations are separate from one another and have their own processes, requirements, and responsible agencies. If you want to know more about the work that goes into these lists and how they come to be, check out our 2023 blog post: Noxious Weeds & Prohibited Plants: A Listing Guide
Common ivy has been a listed Noxious Weed since 2002. It is a Class C Non-Regulated Noxious Weed, meaning that it is confirmed to be introduced to Washington state (non-native), spreads beyond where planted, is difficult to control, and has an impact; but is too widespread to legally require its control. This legal classification does not ban its sale or transport.
As of 2025, Common ivy is now additionally a listed Prohibited Plant. It was 1 of 19 new species that were officially added to the Washington State Prohibited Plant List. Species on this list cannot be transported, sold, or distributed in Washington state. This update went into effect August 9th, 2025.
See the Rule Making update here: WSDA 2025 Prohibited Plant Listing Update
What the experts say
We wanted to know why and how common ivy suddenly appeared on the Prohibited Plants List after decades of impact, so we asked around. The Q&A below summarizes the answers of those that we spoke with.
Special thanks to Scott Brooks (WSDA Plant Services Director), Alison Halpern (Former WA Nox. Weed Board Exec. Secretary), Kristi Park (BioDesign Studio owner/petitioner), and Tom Erler (WA State Nox. Weed Committee Member) for helping us get a clearer picture on the matter.
Q & A: click on a question below to see its response.
How & why can a Noxious Weed be sold in the first place? Shouldn’t all Noxious Weeds be automatically banned from sale?
For that to happen, we would need to add or amend existing state laws. The Noxious Weed List comes from the Noxious Weeds Law (RCW 17.10) and The Prohibited Plants List comes from the Insect, Pest, and Plant Diseases Law (RCW 17.24). The two laws have evolved separately to have their own processes and responsible agencies. While there is good overlap between the two lists (111 of the 164 Noxious Weeds are also Prohibited Plants), there’s currently no legal requirement for the two lists to match.
Why wasn’t common ivy already on the Prohibited Plants List?
To be added to the Prohibited Plants List, a species has to be formally petitioned for inclusion. That petition must be approved by the WSDA director. Until recently, no one had ever officially petitioned to add common ivy to the Prohibited Plants List. This is likely because those willing to make a formal proposal know that to approve a petition, the director must consider the impacts of the listing on local businesses. When ivy was listed as a noxious weed in 2002 it was still a popular, albeit declining, landscaping plant. The concern that its listing would be rejected due to its potential impact on local businesses likely deterred many from petitioning for its listing. Internally in the early 2000’s, WSDA held informal discussions about this but did not pursue listing due to similar concerns.
What changed?
Nursery stock and landscaping preferences! It takes time for the impact of potentially invasive plants to be made clear. Ivy was planted largely as a groundcover for decades. As it became clear that landscaped ivy could easily spread to natural areas and cause impacts beyond its initial planting grounds, and as the noxious weed list became a more widely used reference tool for gardeners, the plant became less popular as a landscaping choice. With less demand from landscapers and increased awareness of nursery owners, stores slowly stopped selling this plant for outdoor use.
So…why/how now?
With a decrease in popularity, a successful petition became more feasible. All that was needed was someone to submit a formal proposal…and it happened!
- In May 2023, a local business owner (Kristi Park – BioDesign Studio) petitioned to WSDA Plant Services for common ivy to be added to the Prohibited Plants List: “(Not) Down with English ivy” petition
- Kristi’s extensive outreach asked that groups and individuals submit written comment in support of the petition and invited folks to attend and testify at the public hearing. “So close to an ivy quarantine! Take action!”
- In that time, the petition received 1200+ signatures, and the WSDA received 22 written comments and 7 oral comments in support of ivy’s listing, including us here at King County Noxious Weeds: WSDA Official Summary Document (PDF)
- The petition and its corresponding testimonies were then reviewed by WSDA, and with the approval from WSDA’s director, 19 new species were adopted on July 9th, 2025, and went into effect one month later on August 9th.
What about local businesses (namely nurseries)?
The Nursery Advisory Committee is a group of nurseries that represent different sectors of the industry, it has a large role in the listing of Prohibited Plants. The consensus was that common ivy is not widely sold or used in landscapes at this point in time.
A “small business economic impact survey” was sent out to stakeholders by WSDA as a legal part of the process; in this case the survey went out to ~4,000 nurseries that were given 6 weeks to respond. Of the 92 responses (which is notably a high response rate for this sort of survey), only 5 affirmed that they sell Common Ivy. The respondents were asked to estimate their total annual sales of the plant, of which the highest seller noted their estimated revenue from ivy as “About $2300 yearly…0.5% of total annual sales”.
See the questions and results in section 4 (pages 7-13) and other evaluated impacts in sections 5 to 8 of the final report: WSDA 2025 Prohibited Plants List – Official Rule Making Document
How is this enforced?
Compliance is largely voluntary, and education based.
In-person sales: all licensed nurseries were informed of the updated list after it was adopted in July and given 1 month (until August 9th) to destroy any of the listed Prohibited Plants that they have in stock. WSDA Plant Services staff perform plant inspections and work with the nurseries as needed to encourage compliance.
Online sales: WSDA has 1 staff who works part time on online sales education and tracking prohibited plant sales on the internet. WSDA has specific contacts with larger online vendors like Amazon and Ebay who have filters in place so that Prohibited Plants can’t be sent within state bounds. On Etsy they connect with individual vendors, taking an educational approach and ask that that they update their selling pages to say that the plants can’t be shipped to Washington.
You can help too! There are ~7,200 licensed nurseries in Washington state so if you see any of the listed Prohibited Plants for sale online or at a nursery, email nursery@agr.wa.gov with relevant information (species name, nursery/website name, date).
Closing thoughts
Common ivy has been an environmental issue in the PNW for decades. While the ban of sales won’t reverse these impacts, for many it acts as a step in the right direction. Whether or not you knew ivy could be sold up until this point, chances are, you’re relieved to know it’s no longer the case.
What makes this situation particularly special is that this large and impactful development came not from a large industry leader or government agency, but from a small business owner and land steward who cared enough to push for a change. Who, with the support of hundreds of local groups and individuals, was able to get the word out about an impactful invasive species and cause real policy change.
This story illustrates that individual action DOES make a difference. So whether your action is talking to others about the impacts of invasive species, volunteering in your community, or controlling the ivy on your property, be assured in knowing that what you’re doing matters.
Happy weeding!