It's been nearly a year since we last checked in on the wire mesh/ strangulation control method installed at a patch of Japanese knotweed along the Calkins trail at the Intervale Center. If you missed the last post from the 2021 season, you can find it here. So what's been happening?
It's been about two years since the wire mesh was originally laid down, and it may take 3-5 years before any real impact becomes evident. For now, the plants are still there, and at a distance, seem to be doing well.
Plot 3 has been in active management since its initial stewardship activity with UVM NR 206 students where plants were hand-pulled. This method was succeeded by the project in 2019/ 2020, which involved covering the ground in wire mesh and allowing the plants to basically self-girdle when the stalks grew too wide for the mesh openings.
Mid July 2022, we took a walk to the patch and got down among the stalks to see how the mesh was holding up. The first thing that we noticed was that the patch had grown beyond the original bounds of the mesh by a couple of feet. As we worked our way into the patch, it was dotted with dead stalks that had been strangled and dried out. Many stalks were shooting roots out to reach the ground around where they were being strangled, and seemed otherwise healthy. There were also many stems that were narrow enough that the mesh came close but just seemed to be a tight squeeze.
Scattered throughout the patch are dead, standing stalks, presumably strangled, making up perhaps 1 out of 25 stalks present. In comparison with other knotweed sites around the Intervale, it does seem that this site lacks some vigor, though it's difficult to tell if that can be attributed to the wire mesh.
The efficacy of this experiment should become much more clear in the next couple of years as we enter the third year in the summer of 2023.