State-licensed crews will begin spraying herbicide on invasive phragmites and knotweed along Oakland County roadways Monday, Aug. 24, in an annual effort to control plants that block intersection sightlines and pose fire risks.
The Road Commission for Oakland County announced the treatment program Wednesday, Aug. 19, in partnership with the Oakland County Cooperative Invasive Species Management Area, or CISMA. Crews will work through late October using vehicle-mounted hand-spray equipment.
Yellow warning signs will appear at each treated site on the day of application. The signs will list the products used, any restrictions and the treatment date. The road commission advises residents to stay out of treated areas until the herbicide has dried.
Why it matters
Phragmites is a reedy grass that thrives in wet areas and can grow 15 feet tall. Dense stands block drivers' views at intersections, clog drainage systems, damage infrastructure and crowd out native plants. When dry, the reeds fuel fires that burn at temperatures up to 2,000 degrees Fahrenheit.
The risk is not hypothetical. In March 2011, a phragmites fire burned 160 acres near Great Lakes Crossing Mall in Auburn Hills, roughly 10 miles from Rochester Hills, forcing the closure of I-75 and the evacuation of nearby homes and businesses.
Knotweed spreads rapidly, especially when cut, and can damage roads and drainage structures.
Both the City of Rochester and the City of Rochester Hills are active CISMA partners in the effort. The coalition and RCOC have run the program together for at least five years, according to the Michigan Invasive Species Coalition. CISMA coordinator Patrick Canniff, based at Oakland County Parks, oversees the partnership, which has grown from 19 founding organizations in 2014 to 45 members.
Who's doing the work
Two contractors hold the treatment assignments. Stantec, based in Brighton, will handle all knotweed treatment and share phragmites duties with PLM Lake and Land Management Corp of Morrice. Both firms are state-licensed commercial applicators.
In an Aug. 7, 2025, press release announcing the same program, the road commission called chemical treatment by a state-licensed applicator "the only effective way to deal with knotweeds and Phragmites."
How to get answers
RCOC has not published a list of specific roads or intersections scheduled for treatment. Residents with questions about products or application methods can contact Stantec at 616-847-1680 or PLM Lake and Land Management at 800-382-4434. General questions go to RCOC at 877-858-4804 or [email protected].
