Japanese Knotweed (common names fleeceflower,
Mexican bamboo, huzhang)
Japanese Knotweed, scientific name Fallopia
japonica, was introduced to the United States from Asia as an
ornamental plant in the late 1800s.
plant is very successful in the US and other countries, and is considered one
of the world’s worst invasive species.
Japanese Knotweed is a strong grower and
can damage manmade structures such as building foundations and roads, and can
create a flood hazard by blocking drainage ditch flow. It grows densely and crowds out other
herbaceous species. Its root structure, or
rhizomes, can survive a wide range of temperatures, and because of their depth,
make removal by excavation very difficult.
It re-sprouts from the root system so cutting does not control the
plant. Applying herbicides is the most
effective method of control, at a time in late summer or fall when the plant is
close to flowering. Researchers are also
exploring biological pest control using the jumping plant louse Aphalara itadori and a leaf spot fungus
from genus Mycosphaerella.