- Knotweed can reproduce through small fragments. Do not dig, cut or mow knotweed as this can stimulate an increased spread.
- Chemical control is the only viable treatment option for large infestations. Click here for a list of Herbicide Contractors in the Kootenays
- Do not grow knotweed in your garden or share cuttings of existing plants, be PlantWise and use Grow Me Instead to avoid planting knotweeds.
- 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.