Japanese knotweed Reynoutria japonica is a highly invasive plant. The plant is spreading rapidly in Henderson County, popping up in new places all the time. The plant is prevalent on roadsides where it thrives in the sun. As you can see in this distribution map, the plant has spread up and down the northern two-thirds of the entire east coast.

Learn more about the plant at the NC Plant Toolbox

Japanese knotweed spreads by seed and root suckers. Each plant can produce thousands of tiny seeds. The root system of a single plant can cover an area half the size of a football field.

Controlling Japanese knotweed requires persistence. Repeated foliar applications of glyphosate and 2,4-D + tryclopyr over 3-5 years is usually required to eradicate the plant. Any seedling that pops up in the future should be treated as soon as they are encountered. The one thing that you should not do is cut Japanese knotweed stems. This stimulates the plant to spread further underground and create new shoots. Seed heads can be removed in late summer and fall to reduce the seed count in the environment.

***Use caution when using pesticides. Read the label of the product thoroughly and follow the instructions for proper use exactly.