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 addition to the natural environmental 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.
The Province of British Columbia has developed their own “Pest Management Plan” (PMP). Pitt Meadows does not require a pest management plan if Licensed contractors are used, as the applications will be recorded on the “Pesticide User License” (PUL) of the contractor.
During the invasive plant’s growing season, the City of Pitt Meadows leverages pesticide applicator contractors and crew members to address noxious weed infestations on City owned lands and road Rights of Way. We continue to work with the Metro Vancouver Invasive Plant Council and neighboring municipalities towards the implementation of a long term regional plan. It is estimated that any areas that are identified as “control areas”, may take up to 4 years to eradicate and requires consistent monitoring by City crew.
The Metro Vancouver Invasive Plant Council reported very high efficacy rates (plant kill) with foliar applications, which is not typical. They have also been applying pesticides via injection, which uses up to 80 percent more chemical than foliar applications. Glyphosate is considered to be effective in the control of Japanese Knotweed and is readily available to both residents and contractors. The Metro Vancouver Invasive Plant Council have also been using other chemical products, however staff do not support their use at this time, due to the reported residual effect on the soil.
Glyphosate is a non selective systemic herbicide, therefore, care must be taken not to kill or damage non target species when foliar spraying. Any chemical application should be carried out by certified professionals.
The B.C. Weed Control Act imposes a duty on all land occupiers to control designated noxious plants. The purpose for the Act is to protect our natural resources and industry from the negative impacts of foreign weeds.
We recommend that citizens contact a qualified business whose applicators have the ‘Pesticide User License' certification. While we know that some may be tempted to take the ‘DIY' approach, the concern is that the foliar spraying of invasive plants in the wrong concentrations or under the wrong conditions may end up doing collateral damage to other plants in your garden, or your neighbour's garden.
If you spot an invasive plant, please contact our Environmental Stewardship Officer at 604.460.6720, or email firstname.lastname@example.org and your concerns will be noted and responded to in the appropriate manner. All information is compiled and prepared for the coordinated control program.
To identify which type of invasive plant species you’ve encountered, please visit the ISC Website.
We continue to work with other levels of government and local environmental groups to ensure that we develop a detailed inventory of invasive plants found in our parks, water courses and protected lands.
There are four species of knotweed that may occur in Pitt Meadows: (1) Japanese knotweed; (2) Giant knotweed; (3) Bohemian knotweed; and (4) Himalayan knotweed.
They originated from Asia and were brought to British Columbia as an ornamental plant. They’re known as one of the 100 worst invasive species internationally and top 10 for control in our province. Knotweeds are designated as provincially noxious under the Weed Control Act. Section 2 of the Act “Duty to control noxious weeds” states that “an occupier [i.e., land owner or other] must control noxious weeds growing or located on land and premises, and on any other property located on land and premises, occupied by that person” ([RSBC 1996] Chapter 487).
According to the Invasive Species Council of BC (2018), both root and stem fragments can regenerate — making knotweeds very easy to spread. Knotweeds successfully reproduce vegetatively and by viable seed. Plants are often spread through contaminated equipment and soil, and improper disposal of removed plant material. Plants are also dispersed through wind, wildlife, cutting and mowing, flooding events and through human actions such as selling, purchasing, and trading knotweed plants.
Knotweeds have significant economic, ecological, social impacts. Most notably is their damaging effect on infrastructure as their vigorous growth can penetrate through concrete and asphalt. The United Kingdom estimates $3 billion USD annually to control this species, and examples of people who have been unable to secure insurance or a mortgage on knotweed-infested properties (ISCBC 2018).
An Integrated Pest Management approach is essential to identify, inventory, assess risks, prevent, control planning and implementation, and monitoring invasive plant populations. Managing knotweed species is challenging. Biological and mechanical controls are currently being researched. Chemical control with a systematic herbicide is currently the “recommended treatment strategy for knotweeds due to their extensive root structure and aggressive growth and reproduction. This treatment method is the easiest, most cost effective, and successful treatment method. Knotweeds typically require treatment with herbicide for 3-5 years” (ISCBC 2018). The City of Pitt Meadows has been closely monitoring, mapping and controlling knotweed growth on City properties. The City continues to contract professional services with certified pesticide applicators to treat and monitor knotweed growth with an herbicide twice a year on City properties, in accordance with best practices.
*Important: Mechanical control on its own is not an effective management tool. Manual control is only recommended under specific circumstances and should be carried out with extreme caution due to the likelihood of spread through root and stem fragments. Mechanical control is a time consuming treatment option that will require dedication of frequent removal over numerous years. All removed plant material should be disposed of properly (see disposal section). (ISCBC 2018).
What you can do to help:
- Report knotweed observations to the City’s Environmental Stewardship Officer by email or call 604.460.6720.
- Do not purchase, trade, or grow knotweed. Choose regional native plants instead. Please see the Invasive Species Council of BC’s Grow Me Instead booklet.
- Maintain or establish healthy plant communities
- Removal of knotweed plant material from clothing, footwear, pets, vehicles and equipment
- Ensure soil, gravel, soil, bark mulch and other fill material are not contaminated with knotweed plant material
- Bag or tarp knotweed plant material then transport to a designated disposal site (eg: landfill)
For more information on knotweed, please refer to following links below:
- Invasive Species Council of BC – Impacts of Invasive Species
- Invasive Species Council of BC – Knotweed information
- Weed Control Act
- Weed Control Regulation – Designation of noxious weeds (Schedule A)
- Integrated Pest Management Regulation
- Invasive Species Council of BC (ISCBC). 2017 - Knotweeds Factsheet. July 2017
- Royal Statute of British Columbia (RSBC). 1996. Weed Control Act [RSBC 1996] Chapter 487. Updated August 15, 2018.
- Hiring a qualified contractor for removal
- Stop the spread of invasive species
If you see Japanese Knotweed, or signs indicating the plants being treated, avoid contact and keep pets away. If there is contact with plants that have been treated and should any skin irritation occur, wash affected areas with soap and water.
Giant Hogweed is an invasive plant that resembles cow parsnip, but can grow up to five meters (15 ft.) tall. The large, hollow, central stalk is green with purple spots. The dark green, coarsely-toothed leaves are divided into three segments. Small white flowers grow in a large, flat-top, umbrella-like cluster, which can measure up to one meter across. An individual Giant Hogweed plant can produce 50,000 seeds. Giant Hogweed thrives in wet areas near streams, but is also commonly found along roadsides, right-of-ways, ditch-lines, and vacant lots.
Giant Hogweed is very dangerous when it comes in contact with skin. The watery sap reacts with sunlight and may cause severe burns, blistering, and scarring. Sap contacting eyes can cause temporary or even permanent blindness. Children may be particularly attracted to the plant, and should be discouraged from playing in areas where this plant may be present.
Parrot Feather is the common name for Myriophyllum aquaticum, an aquatic plant and very close relative of the Eurasian Watermilfoil(Myriophyllum spicatum). Neither or these plants are native to British Columbia and both plants are considered to be an invasive weed species. Their ability to colonize water bodies and drainage systems allows these plants to form dense, thick, obstructive layers in slow moving, fresh water sources. These species create a stagnant water source, choking our ditches of the natural flow of water, severely impacting our agricultural and drainage infrastructure.
Parrot Feather forms a dense mat on the water surface while Watermilfoil thrives below surface as its fragile stems are not able to support themselves above water. Both plants cause severe negative impacts to native aquatic vegetation, insect, and fish populations.
|Leaves are above surface and resemble a small fir tree||Leaves rarely emerge from water due to their inability to support the stem|
|Found in aquariums, fresh water lakes, ponds, streams, and canals||Found in fresh water bodies with a sand or silt covered bottom|
|Most commonly spread by plant fragments which are quite hardy and will easily root in the ideal conditions||Primarily dispersed from one body of water to another by water currents, boats/trailers, and fishing gear|
|Biocontrol – none known||Biocontrol – There’s been suggestions that weevils or midge larva helps control the infestation, however, neither has been deemed effective|
Prevention and Control
Both of these invasive species are easily spread through transport. If you are boating, take note of any signs advising that the waters you are occupying may contain Parrot Feather or Watermilfoil. If they do, before you pull your boat out of the water, CLEAN off any leftover vegetation that may have tangled in your propeller or caught on your fishing gear. DRAIN any remaining water and DRY off any gear that may have been exposed to these weeds.
When selecting aquatic vegetation for your aquariums, there are a number of non-invasive plant options to choose from. Visit www.beplantwise.ca for more information.
More information relating to Parrot Feather, Watermilfoil, and other aquatic plants can be found on the following sites: