Smart Gardening and Invasives

Invasive species are plants, animals, and other living things that have been introduced outside of their natural range and can cause harm. They can spread quickly, and sometimes pose risks to the environment, the economy, and to people’s health and safety.

Invasive species can spread in several ways, including:

• Planting invasive species in gardens and yards.
• Moving soil, gravel, mulch, or garden waste that contains invasive plants or seeds.
• Seeds, plant pieces, or insects hitchhiking on shoes, clothing, pets, bicycle tires, or vehicles.
• Illegal dumping of garden and yard waste in parks, forests, ravines, or other natural areas.

How you can help

Everyone can help prevent the spread of invasive species in our environment:

• Plant native species: Choose native or non-invasive plants for your yard and garden. Check out the Grow Me Instead guide to find beautiful, safe alternatives to common invasive garden plants.
• Clean your gear: Brush off boots, clothing, bike tires, and pets after visiting parks or trails so you don’t accidentally move invasive seeds or plant fragments.
• Dispose of garden and yard waste properly: Never dump garden clippings, soil, or yard trimmings in parks, greenbelts, or ravines. Dumping spreads infestations and violates City bylaws.
• Know what goes in the green bin: Many common garden weeds can go in your curbside green cart, but high-risk invasives like Giant Hogweed and Knotweed must NEVER be placed in curbside green carts or home composters.
• Join a community weed pull: Volunteer with local environmental stewardship groups to help remove invasive plants from neighbourhood parks. Some invasive plants are unsafe to handle, so always follow the group’s instructions.

Managing Invasive Plants on Your Property

Some invasive plants can damage property, harm natural areas, or pose health and safety risks.

Under the BC Weed Control Act and City bylaws, people who own or occupy property are responsible for controlling noxious weeds and untended growth on their property. Noxious weeds are plants the province has identified as harmful and requiring control.

Property owners are encouraged to follow regional best management practices developed by Metro Vancouver and the Invasive Species Council of Metro Vancouver (ISCMV) to manage invasive plants safely and effectively.

Invasive Plants to Watch For

Knotweed species  (Fallopia/ Reynoutria species)

Four species of knotweeds are found in BC: Japanese, Bohemian, Giant, and Himalayan Knotweed.

Knotweed is an extremely fast-growing plant that is difficult to remove. It has hollow, bamboo-like green stems with reddish-purple speckles, broad leaves, and small, creamy-white flower plumes.

Why is knotweed a problem?

• Severe property damage: Vigorous roots can break through building foundations, driveways, asphalt, concrete, and retaining walls.
• Environmental Harm: Its thick growth crowds out native plants and can increase erosion along streams and slopes.
• Public Safety Risks: Obscures roadway sightlines and compromises underground utilities.

What should you do if you find knotweed on your property?

Because knotweed spreads aggressively from tiny fragments, property owners are encouraged to follow regional best management practices, which include:

• Don’t mow, cut or dig it up: This can spread the plant and make the problem worse. Even small pieces of its stems or roots can grow into new plants.
• Avoid manual digging: This can stimulate aggressive re-growth, unless the entire root system is meticulously removed.
• Consider professional control: It’s recommended to consult a licensed, certified pesticide applicator or invasive species specialist, as chemical or targeted professional treatments are typically required for long-term control.

For more information, you can check out the Best Management Practices for Knotweed Species in Metro Vancouver Region and the Knotweeds Factsheet.

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Giant Hogweed (Heracleum mantegazzianum)

Giant Hogweed is a very large invasive plant that can grow up to 5 metres tall. It has thick stems with purple spots and coarse hairs, large deeply cut leaves, and umbrella-shaped clusters of small white flowers.

⚠ Health and Safety Warning: Toxic sap can cause serious burns.

Giant Hogweed contains sap that can cause severe skin burns and blisters when exposed to sunlight. The sap can cause serious eye injuries.

If you are exposed to Giant Hogweed sap:

• Wash the affected skin with soap and water as soon as possible.
• Keep the affected area covered and out of sunlight.
• Seek medical advice. If the sap gets into your eyes, rinse them immediately with water and seek urgent medical attention.

What should you do if you find Giant Hogweed?

Because Giant Hogweed poses a safety concern, it’s important to familiarize with best management practices to ensure safety. These include:

• Don't touch or attempt to remove it: Giant hogweed can cause serious injuries, even if you don't notice symptoms right away.
• Keep children and pets away: Avoid contact with the plant and its sap.
• Contact a professional: A qualified invasive plant specialist can safely assess and manage the plant.
• Don't put it in your green bin: Giant hogweed requires special handling and disposal. Contact an appropriate disposal facility before transporting any plant material.

For more information, you can check out the Giant Hogweed Best Management Practices or the Invasive Species Council of BC's Giant Hogweed Factsheet.

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Other Common Invasive Plants

Visit the Invasive Species Council of Metro Vancouver website for more information about these (and other) invasive plants in our region:

• Himalayan Blackberry (Rubus discolor)
• English Ivy (Hedera helix)
• Scotch Broom (Cytisus scoparius)
• Policeman’s Helmet (Impatiens glandulifera)
• Yellow Lamium (Lamium galeobdolon)
• Field Bindweed / Morning Glory (Convolvulus arvensis)
• Purple Loosestrife (Lythrum salicaria)

Invasive Insects and Other Wildlife

European Fire Ant (Myrmica rubra)

European Fire Ants are small, reddish-brown ants that build dense, moundless nests in lawns, gardens, and under rocks or wood. They are aggressive defenders of their territory and deliver painful stings.

How can you prevent European Fire Ants from spreading?

• Check plants and soil: Inspect potted plants, soil, mulch, and other garden materials before bringing them onto your property.
• Avoid moving infested materials: Ants can spread when plants, soil, or other materials are moved from one location to another.
• Get advice before treating an infestation: European fire ants can be difficult to control once they become established.

For more information, check out the European Fire Ant Best Management Practices.

Helpful Resources

For comprehensive identification guides, disposal information, and best management practice documents:

• Invasive Species Council of Metro Vancouver (ISCMV): iscmv.ca
• Metro Vancouver Best Management Practices Guides: metrovancouver.org
• Invasive Species Council of BC (ISCBC): bcinvasives.ca

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