Knotweed removal effort seems successful

Non-native invasive plant species have long threatened the health of ecosystems, wildlife habitat and populations of native plants in the Lewis Creek watershed. Management can be difficult because they are easily spread via seeds, roots, fragments, animals and humans.

Japanese knotweed is a particularly tough plant to remove. It was introduced from East Asia in the late 1800s, planted as an ornamental and for erosion control (but ironically, can actually increase streambank erosion).

It spreads primarily by its roots or rhizomes, which can break off during a flood then resprout and form a new colony downstream. In 2024, the Lewis Creek Association recruited community members to begin a long-term project controlling knotweed without herbicides in the watershed.

In 2024, Lewis Creek Association and volunteers controlled three populations of Japanese knotweed along Lewis Creek near Old Hollow Road in North Ferrisburgh, while educating the public about how to perform non-chemical knotweed control on riparian properties. Two Lewis Creek Association knotweed-removal technicians, supervised by consultant Michael Bald of Got Weeds?, implemented non-chemical control work at the demonstration site over 16 weeks, with the help of 15 volunteers.

Almost weekly volunteer knotweed removal and education sessions were offered on site. A management plan for knotweed removal at the demonstration site in North Ferrisburgh and two other sites in Starksboro was developed.

Lewis Creek Association also mapped knotweed in a portion of the Lewis Creek watershed using community science tools (iNaturalist). The Lewis Creek Association website now has educational materials about knotweed, the resulting map of knotweed distribution and directions that detail how to participate in our iNaturalist project.

In the future, the association plans to continue a long-term knotweed removal project in North Ferrisburgh and expand the removal-demonstration sites to include sites in Starksboro. It will also be continuing our iNaturalist project and needs your help because there are many knotweed patches that haven’t yet been mapped.

If you see knotweed growing in the Lewis Creek watershed, please snap a photo and upload it to iNaturalist and join the mailing list, so you know when our knotweed removal demonstration days will be held in 2025. You can learn more and sign up.