When Plants Attack

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Japanese knotweed flowers

Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Japanese knotweed was originally introduced to the U.S. from Asia as an ornamental plant. It was also used for erosion control.

Japanese knotweed is a tall shrub with big leaves. It can grow over 10 feet tall. The leaves are oval, with a point at the tip, usually about six inches long. It puts out pretty, greenish-white flowers in summer, which turn into small fruits with wings.

Over short distances, Japanese knotweed spreads mostly by sending out rhizomes, root-like stems that grow along the soil. It usually gets to new sites in deliveries of dirt, and can also be spread by water and occasionally by wind.

If you have Japanese knotweed in your woods, you have options for controlling it.