Japanese Knotweed

Description:

Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not closely related. While stems may reach a maximum height of 3–4 m each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. It is listed by the World Conservation Union as one of the world's worst invasive species. It is a very fast grower that can reach a height of 10 feet and overtop native vegetation very quickly. This plant is a threat to native vegetation because it often forms dense patches, which shade out all other plants. The invasive root system and strong growth can damage concrete foundations, buildings, flood defenses, roads, paving, retaining walls and architectural sites. It can also reduce the capacity of channels in flood defenses to carry water. It forms thick, dense colonies that completely crowd out any other herbaceous species and is now considered one of the worst invasive exotics in parts of the eastern United States.

Habitat:

Native to Eastern Asia in Japan, China and Korea. The weed can be found in 39 of the 50 United States and in six provinces in Canada. It is listed as an invasive weed in Maine, Ohio, Vermont, Virginia, West Virginia, New York, Alaska, Pennsylvania, Michigan, Oregon and Washington state.

Notes:

Spotted growing on a wooded drive near an old church and cemetery and a utility plant.