Invasive plants, such as Japanese Knotweed and Swallow-Wort, seem to have become more prolific in our area. This is not an experience unique to us in the Northeast USA but is something we are learning to deal with worldwide. In some cases, invasives have entrenched themselves so well that not even digging them out is an effective form of control and some treatment is required. For maximum invasive elimination, expect to continue control efforts for 2-5 years, or even longer, to deplete the seed bank. Treatments should be at least 50’ from the waters edge. Plants should be bagged in plastic and disposed of in the trash to prevent seed dispersal or re-rooting.
Glysophate is the best option as it is a non-selective herbicide, it has no soil activity and has low toxicity to nontarget organisms. Selective Broadleaf herbicides such as triclopyr can be used but are less effective, however, it would not harm grasses.
If the treatment is required near a waterway, there is an aquatic glysophate option available (avoid spraying directly into the water).
As with all invasive plant eradication, long term succession planning is ideal to replace with stands of native species.