Weed of the Week - Japanese Knotweed

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Japanese knotweed (Fallopia japonica) is becoming more and more evident in landscapes, parks, open lots, and roadsides across Ohio. The non-native plant has taken hold in a small park in NW Ohio and management attempts are currently underway. The photos were taken a couple weeks ago. 


Japanese Knotweed
Photo Credit: Amy Stone, OSU Extension-Lucas County


Characteristics of the plant include:

  • Perennial, herbaceous type-shrub that can grow from 3-10 feet high each year
  • Stalks are hollow and persistent through winter, looks similar to bamboo
  • Stems have a fine white coating that rubs off easily
  • Flowers arranged in spikes near the end of the stem are small, numerous, and creamy white in color
  • Flowers bloom later in the summer in Ohio
  • Prolific seed producer


Japanese Knotweed
Photo Credit: Amy Stone, OSU Extension-Lucas County


We are encouraging folks to report locations of where this plant is growing using the Great Lakes Early Detection Network (GLEDN) app. If you have not used the app before, it is an easy app that includes invasive plants, insects, diseases, and wildlife. The app uses the EDD maps were locations of the reported species are indicated once verified. For additional information about the GLEDN app, check out the website or search your app store on either your iPhone or android phone at https://apps.bugwood.org/apps/gledn/