Do not grow knotweed in your garden or share cuttings of existing plants.
Description
Native to eastern Asia (Japan, China, Korea).
There are three varieties of knotweed (Fallopia spp., Polygonum ssp.) present in our region: Japanese, Giant and Bohemian knotweed, all have similar characteristics and concerns.
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.
Introduction and spread
Knotweed was initially introduced to BC for ornamental use, especially for privacy purposes as it grows rapidly and forms dense patches.
The plant reproduces through fragmentation, so when small pieces of the plant are moved by mowers, equipment or other vectors it can allow the plant to spread.
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 property value.
Status in the CKISS region
Giant, Japanese and Bohemian knotweeds are classified as Contain for the CKISS region on the CKISS Annual Priority List.
This means that they are abundant in some parts of our region, but not widespread across the entire region.
The goal is to prevent knotweed from spreading to new areas.
Himalayan knotweed is considered Regional EDRR in the CKISS region as it has not currently been found in our region.
