Facts

• Knotweeds are members of the Buckwheat Family (Polygonaceae) that originate from volcanic regions of Asia
• All species of knotweeds are extremely fast growers, reaching heights of 6 -15 within a single growing season. Plants usually attain their full height by June - July, and go to flower in July/August
• Growth typically starts in early April, but may start later at higher elevation
• Commons names often include False Bamboo, Elephant Ear, and Fleeceflower

Scientific Names
Scientific names include:

• Bohemian knotweed (Polygonum X bohemicum)
• Giant knotweed (Polygonum sachalinense)
• Himalayan knotweed (Polygonum polystachyum)
• Japanese knotweed (Polygonum cuspidatum)

Characteristics

• Depending on the size, age, and site location of the plant, rhizomes can penetrate up to 7 feet into the soil, making control very difficult
• Flowers are grown out of leaf axils, and are white to greenish in color
• Leaves are alternate and bright green
• Manual control activities tend to aggravate the plant
• Plants can send up young shoots late into the growing season, especially in response to treatment activities
• Plants die back after the first major frost of the year
• Rhizomes are brittle and orange in color, much like that of a carrot
• Rhizomes can send out shoots up to 20 - 25 feet away from the mother plant
• Stems are thick and hollow, resemble bamboo, and are green to reddish in color
• Tall, very aggressive perennial species
• While plants are dormant for the winter, the dead brown canes persist throughout the winter months, creating an unattractive landscape