Based on a presentation by Bob Williams, www.phragmites.org
In the Great Lakes region, September is prime time for treating phragmites with herbicide—which, at this point, is a key part of effective control. In September, the reeds are transferring nutrients down to the roots, making herbicide transport more thorough. Plus, in most years, the ground is dryer in August and September, expanding the area where non-wetland-approved chemicals can be used. That’s an especially critical factor in Ontario.
But if you didn’t start planning earlier this year, chances are you didn’t spray in those months. Is there a way to get started now on controlling phragmites? Yes! Plan to cut dead stems this winter.
Phragmites (Phragmites australis) is an invasive plant taking over marshes and wetlands across our region. Each fall, stems die for the winter to be replaced by new growth in the spring. Cutting the already-dead growth won’t, by itself, slow down the phragmites. But cutting dead growth will make your control more effective next season by making it easier for the herbicide to reach the target, live tissue. In the photos below, the phragmites on the top was not cut and includes a high proportion of old stems. The phragmites on the bottom was previously cut, and all that green growth is a good place for herbicide to land.
Cutting after the ground freezes allows use of mechanical equipment without churning up mud. It will also be helpful to cut again in late July to stress the plants and keep them shorter, making spraying easier. Avoid cutting April 15 – July 15, when nesting birds may be present. Be sure to leave four weeks between your cut and the time when herbicide will be applied.
As you’re getting a first cut done, perhaps starting with a small area, you can also begin planning for resources, supplies, any permits needed, and follow-up for a control next year. For the more information, see Michigan Department of Environmental Quality web info, or the Ontario Ministry of Natural Resources’ Best Management Practices document.
A highly practical guide can be found at www.phragmites.org, based on years of experience by Bob Williams of Harsens Island, Michigan.