An imported species once favoured in Victorian gardens for its ability to provide privacy screens, Japanese knotweed has jumped the garden wall in B.C. and is now rampant in lanes, roadways, stream banks, along highways and on private property ranging from city lots to rural acreage. The weed, often called “mock bamboo”, can bust through concrete foundations, asphalt roads and even metal.
Japanese knotweed is now in many B.C. regions, found in six provinces in Canada and 39 of 50 U.S. states and is on the World Conservation Union’s list of 100 worst invasive species.
There is some call for putting it on property disclosures. Some say it should rank up there with grow operations in terms of the hidden threats for clients purchasing property or developers hoping to build on a site.
The B.C. Real Estate Association (BCREA) wants to prevent knotweed from reaching the levels realized in many European countries.
Liability issues are also becoming an increasing concern. Real estate agents will need to ensure the client buying a home is investing in something that is not potentially losing value. If the land is going to be developed, the contractor needs to ensure that the guarantees in place remain intact and are not shattered by a weed bursting through a wall or foundation.
Even the 2012 London Summer Olympic’s velodrome and aquatic centre site, which was plagued by the invasive species. In March 2007, the Daily Mail online reported: “Japanese knotweed could add £70 million to the cost of staging the 2012 Olympics. Specialists can charge up to £40,000 to clear only six square yards of ground affected by the weed, which has been called the most invasive plant in Britain.”
The plant was subsequently blamed for part of the cost over-run for the site development, which included demolishing buildings, building tunnels, clearing up contamination and constructing new buildings on the Olympic site housing the aquatic centre and the velodrome.
Clearing sites of the weed is difficult and herbicides are the only ready solution.
The bamboo-like shrub can grow three metres in height and has a root system that can travel down nine metres and laterally 28 metres. It can regenerate from pieces as small as a finger. It has been added to the B.C. Weed Control Act, which means landowners must control the plant.
In the U.K., Grenz says, insurance companies have refused to provide coverage for building sites known to have knotweed.
It is also a concern to people who are buying ranch land because it can erode land values, clog streams and incur a substantial clean-up bill.
The good news is that regional districts and municipalities are developing active programs on their lands.
For more information visit http://www.iscmv.ca.
MRG Properties 