Perth County continues discussion on invasive-species strategy

Perth County council is continuing its discussion on how best to address the growing threat posed by invasive plant species, including whether funding set aside for giant hogweed eradication could support a broader, coordinated approach across the county.

After hearing from Upper Thames River Conservation Authority (UTRCA) forestry and restoration supervisor Rob Davies about the conservation authority’s collaborative invasive-species program at its March 5 meeting, council revisited the topic during discussion of the county’s 2025 weed report at its March 19 meeting.

Councillors considered whether some or all of the $25,000 included in the 2026 budget to address giant hogweed could instead be used to support broader efforts to map, monitor and control invasive species across the county.

“This is probably an opportunity to address what was carried over from a few meetings ago with regards to the money we had set aside for invasive species,” Coun. Walter McKenzie said, putting forward a motion proposing the funding be used, in whole or in part, to support invasive-species control on public lands and roadsides, particularly to address the spread of giant hogweed, phragmites and Japanese knotweed – three of the most concerning plants currently affecting Perth County.

“ … There may be other invasive species, but those are the three that we talked about, and those are the three that seem to be an issue in, certainly, the southern part of the county. … I’m not looking to spend the whole $25,000; let’s take what it needs and spend up to $25,000, but if we don’t need it, we wouldn’t spend it. I think we still have to have a follow-up (report) at some point in time to make sure this program is working.”

According to public works director Bill Wilson, however, Perth County already has a roadside-vegetation management program that allows its weed-control contractor to identify and treat invasive species along county roads, including phragmites. Council heard this work could potentially be expanded to include local municipal roads in the future as mapping efforts improve.

The UTRCA program aims to create a coordinated strategy to identify, map, monitor and control invasive species across the watershed, with a focus on the three of most concerning weeds mentioned by McKenzie. These species are considered particularly problematic due to their environmental, economic and human-health impacts.

Giant hogweed, for example, produces a toxic sap that can cause severe skin irritation, blistering and long-term sensitivity to sunlight when it comes into contact with skin. The plant can also reduce biodiversity and limit recreational use of natural areas.

Japanese knotweed is known for its aggressive root system, which can damage infrastructure including foundations, bridges and drainage systems, while also crowding out native vegetation and reducing biodiversity.

Phragmites, an invasive grass species, spreads rapidly in wetlands and roadside ditches, forming dense stands that disrupt water flow, increase fire risk and create challenges for municipal infrastructure maintenance.

The county’s weed report notes that complaints in 2025 included issues related to giant hogweed, sow-thistle and dog-strangling vine, as well as growing concern about invasive species not currently listed as noxious weeds under provincial legislation, including phragmites, garlic mustard and Himalayan balsam.

The UTRCA’s program is designed to address these concerns through a collaborative, multi-year effort involving municipalities, conservation authorities, industry groups and private landowners. The approach emphasizes early detection and rapid response, as well as prioritizing areas where coordinated treatment can produce long-term results.

“I think we do need to seek clarity … on whether we’re going to give some money to the conservation authority or whether we’re going to essentially keep it for our own team’s purposes and focus our efforts on our own land, leaving the ratepayers to pay their own bills on their land in terms of weed control,” Coun. Todd Kasenberg said. “I do have vague concern about that notion that if we leave the ratepayer to handle it, those who don’t actually do it exacerbate the problem.”

“I think that we should take a serious look at education because I think there are a lot of ratepayers who really don’t know how big the issue is with some of these weeds,” added Coun. Bob Wilhelm. “Perhaps we need to educate them.”

A key challenge in controlling invasive species is a significant portion of affected land is privately owned, making cooperation from landowners essential to any long-term strategy. According to the UTRCA presentation, fragmented efforts are often ineffective because invasive plants can quickly spread from untreated properties into neighbouring lands, undermining progress made elsewhere.

“Our new approach is a collaborative, coordinated approach to identify, map, monitor, prioritize and control invasives within the Upper Thames River watershed,” Davies told county councillors at their March 5 meeting. “Specifically, we’re going to target giant hogweed, Japanese knotweed and phragmites because we know these species are significant issues across our watershed. The local awareness and local action will get efficient results. We’re looking for partnership between private landowners, municipalities and (conservation authority) lands, and we’re hoping for a sustained, multi-year program.

“The collaborative support of our partners with either access to lands, landowner contacts, identification, monitoring, mapping or control efforts will result in effective, efficient, informed decisions at both the local and regional levels, and it also gives us the ability to leverage those funds to make any investments go that much further.”

Ultimately, council referred McKenzie’s amended motion back to staff for further analysis on how much funding the county could or should contribute to the UTRCA’s program, whether similar services are available through the county’s other conservation authorities (Maitland Valley and Ausable Bayfield) and whether a portion of the $25,000 should remain dedicated to internal control efforts on county and lower-tier land.

“We already pay into the conservation authorities through our lower tiers, so I have a problem if we’re going to give them more money, especially if this program is not one that’s mandated,” Coun. Rhonda Ehgoetz said during the discussion. “To me, it’s over and above. Yeah, it might be a problem; it sounds like we’re already addressing it here at the county. So, I’m not in favour. If Walter’s motion only pertains to the county … I can support that, but I cannot support giving more money to the conservation authority.”

Staff are expected to report back to council with additional information to help guide future decisions about how the county will approach invasive-species management moving forward.