Japanese knotweed (Fallopia japonica) is an invasive perennial and noxious weed in PA. This article will assist with identification and provides recommendations for control, including a management calendar and treatment and timing table.

Information about the noxious weeds known as invasive knotweed (hybrid knotweed, itadori knotweed, giant knotweed, and Himalayan knotweed). Invasive knotweeds are also known by their scientific names, Fallopia x bohemica, Fallopia japonica, Fallopia sachalinensis, and Persicaria wallichii.

Jul 23, 2024 · Japanese knotweed (Polygonum cuspidatum) is a tough, invasive plant. It usually requires a multi-prong approach to achieve complete eradication.

Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. [1][2] Common names include Japanese knotweed[2] and Asian knotweed. [3] It is native to East Asia in Japan, China and Korea.

Jun 14, 2021 · Knotweed is a short-lived perennial that grows from a central taproot to spread its wiry stems outward in a dense mat of wiry stems that are broken by small joints or knots. Those stems are covered with small, blue-green leaves growing alternately from base to tip. There are two common knotweed types.

Japanese knotweed, (Fallopia japonica), herbaceous perennial plant of the buckwheat family (Polygonaceae) native to China, Korea, and Japan. Persistent and aggressive, Japanese knotweed is a noxious weed in many areas outside its native range and ranks among the world’s worst invasive species.

Japanese knotweed is a shrub-like, semi-woody perennial growing up to 9 feet tall. Leaves are simple, alternate, up to 6 inches long by 4 inches wide, and broadly ovate with pointed tips and a square base. Knotweed grows quickly and has hollow, bamboo-like …

Feb 24, 2025 · To get rid of Japanese knotweed, start by using garden shears to cut off the canes as close to the ground as possible. Then, spray a glyphosate weedkiller, like Roundup, on the remaining plant, making sure not to get it on the surrounding vegetation.

Japanese knotweed is native to eastern Asia and was introduced to North America as a horticultural plant in the late 19th century. It can grow in a wide range of habitats including riparian areas, wetlands, roadsides, ditches, and fence lines.

Japanese knotweed thrives in disturbed areas, along roadsides, and on stream or river banks, forming dense thickets that pose a significant ecological threat to riparian areas. Its ability to rapidly colonize an area threatens native vegetation and can greatly alter natural ecosystems.