Lower Raritan Center Mitigation Site Phragmites Control

The Lower Raritan Center Mitigation Site is comprised of over 120 acres with approximately 110 acres of proposed planting, situated along the Raritan River waterfront. The project site is located on a portion of the U.S. Department of Defense’s former Raritan Arsenal.

As part of a Master Plan developed by GreenVest LLC, the goals for the site include the creation of mitigation value and ecological uplift in concert with creating opportunities for future responsible redevelopment of other portions of the larger site for commercial and transportation resources. The primary project objectives include restoration, enhancement, and preservation of freshwater wetlands, open water, and upland maritime forest; riparian enhancement and creation; and invasive species management.

During the late-summer months of 2023, approximately 120 acres of Phragmites (also called common reed) were sprayed with Habitat®, an EPA-registered systemic herbicide, which contains the active ingredient imazapyr. The herbicide application was conducted using an amphibious Marsh Master MM1 machine equipped with a custom sprayer system. The Marsh Master herbicide application took approximately 20 days to complete and was expected to achieve approximately 90% control of the common reed growing within the site.

To ensure the continued mitigation of this highly aggressive and invasive species, additional herbicide applications took place in 2024 and another is expected to be completed in 2025.

During the winter of 2024, Princeton Hydro used the new Marsh Master 2MX-KC-FH amphibious machine to mow, roll, and plow the dead common reed stalks. The operation started with the Marsh Master and rear mounted hydraulic mower attachment; the entire site was mowed using this attachment. Designated areas of the project site containing high amounts of phragmites were cleared a second time, this time with the Marsh Master’s rear mounted roller/chopper attachment and front mounted hydraulic vegetation blade. The roller/chopper attachment “mulched” the common reed stalks further to expose more of the substrate. The front mounted vegetation blade was then used to push or “plow” the common reed stalks to expose even more of the substrate. Exposing the substrate allows for easier planting efforts for native species and provides a suitable environment for native seed bank establishment.

Upon completion of the second herbicide application, the site will be ready for construction and planting of desirable, native and biodiverse vegetation. Future herbicide applications will be conducted using handheld equipment to avoid any damage to the new plantings.