In order be successful managing and controlling invasive plants, we always recommend following best practices  guides and using tools from the Integrated Pest Management (IPM) toolbox. Not all tools and methods are equal, and this all depends on the plant biology. Some methods only suppress the plant instead of kill it, some methods may actually make the infestation worse and larger!

This means that you need to do your research and choose the right tool for the plant.

In order to select the right tool, you need to know:

• What plant you are controlling (ie. identification)?
• What is the plant's biology (ie. how it grows, how it reproduces, time of year)?
• Where is it growing (ie. site conditions, accessability; eg. near water/buildings/etc) ?
• When to target the plant (eg. in the spring before flowering, in the fall as it prepares for winter)?
• How long do you have/What is your timeline?
• What tools do you have access to? 
  • Do you have the physical ability or time to do this work?
  • What costs or budget do you have for treatments?
  • What methods might be ineffective or actually make the infestation worse 
• And most importantly -- What is your plan or maintenance capacity for the space?

Controlling invasive plants is only just the first step -- Also consider:

• How will you conduct follow up treatments
• How you will maintance and keep other invasive plants out, 
• What you want this space to be used for, either by yourself or by our local biodiversity

Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is a decision-making process that includes identification and inventory of invasive plant populations, assessment of the risks that they pose, development of well-informed control options that may include a number of methods, site treatment, and monitoring. There are four primary control options (besides prevention) for the management of invasive plants: cultural control, mechanical control, biological control, and chemical control.

Prevention:

Prevention is the best method of controlling the introduction and spread of invasive plants.

• Learn to identify and control invasive plants using methods suitable to site and species
• Know what you grow - avoid growing invasive plant species; substitute invasive plants for less aggressive species
• Remove plants that are creeping or reseeding outside of their intended area
• Revegetate disturbed areas with regionally appropriate (i.e., native), non-invasive, non-persistent seed mixtures or plants
• Do not dump plants or plant material over the back garden fence or into greenspace
• Clean equipment, tools, vehicles, pets, and shoes before leaving an infested area
• Do not compost invasive plants

Cultural Control:

• Use other plants to help outcompete or shade out invasive plants 
• Ensure soil health to help native plants grow, which prevents invasive plant establishment
• Ensure no bare soil is left that can provide opportunities for invasive plant introductions

Manual/Mechanical Control:

• Tillage/cultivation
• Hand weeding or pulling
• Mowing or cutting
• Excavation (for large scale areas)

Biological Control:

Biological control agents are organisms (usually insects) that can be used to reduce weed populations. These agents are usually the natural enemies of weeds in their native environments.

It takes decades for a biocontrol agent to be approved and released into the wild. Before introduction of a natural agent to Canada is approved, Canadian and United States scientists review exhaustive long-term studies to ensure safety. In order to be released in North America the agent must damage only the target weed and not transfer to any other plants.

Biological control is best suited to large, dense infestations where other management strategies are neither cost-effective nor environmentally desirable. It is intended to weaken the target weed by decreasing seed production and reducing weed density – not to eradicate the weed species.

In the Fraser Valley the following weed species are under biological control, overseen by the BC Ministry of Forests's Biocontrol staff:

• Purple loosestrife
• Canada and bull thistle
• Spotted knapweed
• Tansy ragwort
• St. John's wort
• Hound's tongue
• Dalmatian toadflax

Chemical Control:

Herbicides are chemicals designed to kill or injure plants, and is used when other options are not practical or effective, often on particularily aggressive invasive plants.

All chemical control work is required to be completed by certified pesticide applicators and follow protocols outlined in the Pest Management Plan for the South Coast, as well as provincial and local legislation such as the BC Integrated Pest Management Act.

Trained and experienced practitioners also know to seek out Best Management Practices for the invasive plant they are targeting. There is never a "one size fits all" option, and many decisions need to be made when using herbicides, including:

• application method,
• which product to use, 
• time of day/time of year, 
• wildlife or fish considerations,
• use of space,
• site preparation, and
• post-treatment monitoring and follow up.