Hop Brook Protection Association
2020 marked the first year that the Hop Brook Protection Association has engaged in a concerted effort to manage water chestnut in Grist Mill, Carding Mill, and Stearns Mill Ponds using Clearcast, after many years of trying to mechanically and manually harvest this aggressive, invasive species. Clearcast (or imazamox) developed 1969, is a compound that is absorbed by the leaves and stems of plants, which is transported to the roots, inhibiting the production of a specific enzyme that synthesizes essential amino acids in susceptible plants. Plant growth stops immediately and the plants dies within 4-12 weeks.
As water chestnut seeds are viable to up to 12 years, this will be a multiple year program, funded by Community Preservation Act funds. Below are aerial photos and drone footage provided by the Hop Brook Protection Association showing the effectiveness of the initial treatment.
The second year of treatment was not overly effective due to a number of factors. In 2022, a new consultant was brought on board and we saw marked improvement in water chestnut treatment. Additionally in 2022, US Fish and Wildlife obtained permits to also treat water chestnut in the Sudbury River. These locations are the only known populations of water chestnut in Sudbury. Management in Sudbury will assist not only Sudbury’s waterways, but also communities downstream, minimizing the proliferation of this invasive species, which was first observed in Concord, MA in 1859 and covered approximately 100 acres of our Sudbury’s waterbodies. View the 2022 Treatment Report here for the Hop Brook Mill Ponds and the Sudbury River.
The Conservation Commission is actively working with the Hop Brook Protection Association to ensure safe, effective, and compliant practices are employed by the applicator. The end result will be eradication of water chestnut from these historically significant ponds. We look forward to seeing a reduction in population in the coming years.