Pretty plants can have ugly impacts. This is especially true with knotweed, a fast spreading and potentially destructive plant that is legally designated as a “noxious weed” in British Columbia.
With bamboo-like stems, the plant can cause structural damage by pushing through concrete, asphalt and drainage systems. It also displaces other plant life, causes erosion and pollutes streams with sediment from the eroded land.
It’s advisable that Realtors become familiar with knotweed, so that they can inform clients (buyers and sellers alike) about the risks and give appropriate advice on any related client preferences or disclosure requirements.
What is knotweed?
Native to Asia, there are four knotweed varieties in the province: Himalayan, Japanese, Giant and Bohemian. All grow in the Fraser Valley, but Japanese and Bohemian knotweed are the most common here. While all of them spread quickly, Bohemian knotweed, which is a hybrid between Japanese and Giant, reproduces the fastest.
What you need to know about knotweed
According to the REALTOR® Code, Realtors must act honestly and competently to discover facts to protect the interests of their clients and when dealing with other parties.
The “Key to Identification of Invasive Knotweeds in British Columbia,” cites the following characteristics to help you recognize knotweed:
- densely clustered across a broad area
- bamboo-like stems that are reddish or purply-brown
- heart or triangular-shaped leaves of varying size
- small greenish-white or pinkish-white flowers
- height between 1.5 and 6 metres.
Eliminating knotweed can be a difficult and costly task. Although cutting it down will remove it temporarily, the debris can take root and the plant can start growing again, often more aggressively than before. Rather than mowing it down, it is recommended that knotweed be treated with an herbicide. Even then, it may take several years of treatment to fully eradicate a large area of knotweed.
Given the risks and removal challenges associated with knotweed, a Realtor who knows or suspects that it is growing on a property should advise their client to consult with someone who specializes in weed management. An expert can identify the plant, explain the risks and provide guidance or services with respect to eradication.
The Fraser Valley Invasive Species Society maintains a list of invasive plant management contractors. For your convenience, the contractors are set out below.
Fraser Valley
- Drinkwater Environmental Services, 604.302.2317, drinkwater.es@gmail.com
- Morrow Bioscience, 604.317.1413, info@morrowbioscience.com
- Seven Generations Environmental Services, 604.820.5950, info@sges.ca
- Weed Man Chilliwack, 604.795.4600, chilliwack@weedmancanada.com
- Western Weed Control, 604.462.0637, wwc@telus.net
Metro Vancouver
- Diamond Head Consulting, 604.733.4886, info@diamondheadconsulting.com
- Green Admiral Nature Restoration, 604.317.8903, wmcleod@greenadmiral.ca