Invasive Knotweeds

Invasive knotweeds
(Fallopia ssp. (Polygonum ssp.))


  • Native to eastern Asia (Japan, China, Korea).
  • Herbaceous perennial.
  • Hollow stems, similar in appearance to bamboo.
  • Reach 3-4 m high.
  • May have small cream, white or slightly pink flowers.
  • Reproduces vegetatively.
  • Adapted to moist conditions, generally shade tolerant.
  • Found throughout the region, along roadsides primarily.

Consequences of invasion

  • Invades roadsides, disturbed sites, wetlands, riparian areas and streambanks.
  • Increases erosion and sedimentation of streambanks and riparian areas.
  • Decreases fish habitat and has negative impacts on salmonids.
  • Negatively impacts infrastructure such as asphalt and house foundations by growing through them.
  • May decrease land value.

Integrated Pest Management Options

  • Small Infestations; Digging out the roots, mulching (with cardboard and burlap) and covering with black plastic may work; this will take up to 5 years to control the infestation.
  • Chemical control is the only viable treatment option for large infestations-for more information please contact Kootenay Weed Control, 250-512-7378

More information available:
Central Kootenay Invasive Plant Committee: CKIPC Plant Profile
Invasive Species Council of BC:
King County Washington: