Invasive Plant Species

An invasive species is any plant or animal species that is introduced into an environment where the species is not native. There are numerous examples of plants, insects, birds and animals that have been transplanted from their natural environments, either by accident or intentionally, into areas where they end up having a serious impact on the natural ecosystem.

In 2011, Japanese Knotweed was added to the list of noxious weeds in BC and is covered under the Untidy and Unsightly Premises Bylaw No. 6982 which requires that residents dispose of this and other noxious weeds, when their presence is noted on private property.

Japanese Knotweed is one of over 35 invasive plant species that have been identified in British Columbia.

Maple Ridge has been working on the issue of non-native plant control and management for a number of years. The Lower Mainland has some of the most favourable growing conditions in Canada, and as people moved to this region from all around the world; they brought plants and trees with them to plant on their properties. BC's Lower Mainland has one of the largest diversity of tree species in the nation.

Here in BC there are native plants that have adapted to the unique soil conditions and, unusual environments and harsh climates. These plants, if taken elsewhere in the world, could be an Invasive weed, if taken out of their ecosystem that has natural predators and controls.

Japanese Knotweed was introduced into places in the world as a landscaping plant. In the Lower Mainland, and in other areas of the world, Knotweed has thrived in the soil and moisture conditions and is now pushing out native plant species. In 2011, Japanese Knotweed was added to the list of 'Noxious Weed' species, which allows for more aggressive control strategies.

Noxious weeds that are part of the Untidy and Unsightly Premises Bylaw No. 6982

Canada Thistle (Cirsium arense)
Bindweed or Morning Glory (Convolvulus)
Couch Grass (Agropyon repens)
Purple Loosestrife (Lythrum salicaria)
Giant Hogweed (Heracleum mantegazzianum)
Japanese Knotweed (Polygonum cuspidatum)

Plants evolve in their natural setting, and there is often natural climatic, insect and animal controls that keep them in check. Taken out of their natural environment, these plants have no 'checks' to their growth and expansion, and they can very quickly crowd out native plant species and upset the balance of a natural ecosystem.

Some of these plants provide no food or shelter benefits to the native insect and animal species, and in fact, some of these plants can result in erosions and habitat destruction that can impact fisheries ecosystems.

In addition to the natural environment impacts, some invasive plants can speed up the deterioration of public and private infrastructure. Just as the tree that you planted 20 years ago in the back yard has now grown to the point that the root system is pushing up your driveway, or the Ivy you planted has completely grown over your retaining wall and rooted into the cracks in the concrete or wood ties, invasive plants can accelerate the destruction of man-made materials.

Finally, as was noted, some of these plants are harmful to human and animal life. We've all heard of Poison Ivy and Poison Oak, but there are native and non-native weeds that can cause serious injury to people.

The BC Weed Control Act was put into place to protect the environment from the negative impacts of foreign weeds. There is a long list of plants that have been designated as noxious weeds, and that list grows each year.

This is important, because many communities, including Maple Ridge, have bylaws that limit the use of chemicals to control nuisance weeds. However, when a plant is added to this list, it opens up the use of chemical control methods and moves it outside any Municipal Bylaw.

The BC Weed Control Act imposes a duty of responsibility on the occupier of the land to control designated noxious plants. That has critical implications on private and public land owners.

Maple Ridge has been working on the issues of invasive plant management for a number of years. Our staff has also been working with lands where development is occurring to ensure that invasive plants are controlled in environmental setbacks for periods of up to five years. This is an important part of the overall protection of 'riparian' areas. Riparian areas are the sides of creeks and streams, and the associated natural ecosystem of plants, insects and wildlife.

The Invasive Species Council of Metro Vancouver (ISCMV), formerly the Greater Vancouver Invasive Plant Council, is a non profit society that is working to improve the way we manage invasive species in the Vancouver region. There are many plant species that are not native to our region and each of these can threaten the environment, economy and public safety. The purpose of their website is to provide you with information about invasive species, specific species of interest in our region, control methods, ISCMV's services and to keep you updated on weed-related activities in the region.

There is another organization, the Invasive Species Council of BC (ISCBC), which has been communicating information regarding Knotweed, and other invasive species. For more information please visit their website.

Neither organization is an official department of the BC Government, but are valuable partners in identifying invasive species and reaching out to find best management practices to help control the spread of invasive plant, insect and animal species.

The evidence shows that manual removal, digging it up or chopping the stalks, is not a viable long-term solution. The species of Knotweed that we are dealing with here does not 'seed' like other invasive weeds, however the combination of the deep root network and the fact that even the smallest amount of the plant, under 5 grams of material, can re-root the plant. The Operations Centre and our contractors will be part of the team that develops and implements the control program in Maple Ridge.

The other consistent message that we are hearing from experts throughout the region is that organic chemical controls, such as vinegars, are not effective in controlling Japanese Knotweed.

The method that has the best effect is the use of specific chemicals. There are two methods that are currently being used in the region to curb and control Japanese Knotweed.

The first method is called 'foliar' applications which means that you spray the chemical solution on the leaves of the plant that you are trying to eradicate.

The second method, and one that seems to be the most effective, is the injection of the chemicals into the plant stalks. Japanese Knotweed has stalks that are somewhat like rhubarb, and the injection of the chemical at the right concentration and dosage, carries the biological agent deep into the root system. The correct amount of chemicals and the application equipment is specialized and needs to be done by people that are properly trained and have their "Pesticide User Licence."

The methods that Maple Ridge deploys in dealing with Japanese Knotweed and other noxious weeds is done in ways that ensure that the eradication is targeted and mitigates any impact on native plant species. The most extensive control program will not 'eradicate' Japanese Knotweed in one year. The realistic approach is to develop a well planned and executed control program that systematically and precisely targets this invasive plant over a number of years.

Doing nothing is NOT an option!

Maple Ridge has been dealing with Invasive and noxious plants for a number of years, and the addition of Japanese Knotweed has an impact on every community in the Lower Mainland.

Our current recommendation for private landowners is to ensure that the control of Japanese Knotweed and other noxious weeds is done by an individual or company that has a "Pesticide User License."

Please report any patches of Japanese Knotweed or Giant Hogweed by calling our main switchboard at 604-463-5221 and you will be forwarded to a staff member who will record the information. You can also send us an email.