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