Smart Gardening and Invasive Species

Healthy plants are better able to withstand pests and disease. Good growing conditions are one of the best ways to prevent problems before they start.

Build Healthy Soil

• Test your soil to understand its pH and nutrient levels. A pH between 6.0 and 7.0 is generally suitable for healthy gardens and lawns.
• Improve soil where needed by adding compost or other appropriate organic matter. Mulch can also help keep soil cool and moist, retain nutrients and reduce weeds.
• A layer of approximately 8 cm of leaf mulch, compost or wood chips can help protect soil during the summer.

Choose the Right Plants

Choose plants that are suited to our local climate and the conditions in your yard. Take a look at Metro Vancouver's Eco-Friendly Lawns and Garden's Guide  and the Metro Vancouver Tree Guide.

When purchasing plants:

• Buy from a reputable nursery or garden centre.
• Choose healthy plants with well-developed root systems.
• Look for plants that are naturally resistant to pests and disease.
• Consider native plants that are well suited to local conditions.
• Check whether a plant is suitable for sun, shade, wet or dry conditions before planting.
• Allow enough space and air circulation between plants to help reduce disease.

Resources such as Great Plant Picks and native-plant information from local organizations can help you select plants suited to our region.

Create Variety

A diverse garden can provide habitat and food for birds, butterflies and beneficial insects. Consider combining:

• Perennials
• Annuals
• Vegetables
• Herbs
• Fruit trees
• Native plants

Avoid planting large areas with only one species where possible. A variety of plants can make your garden more resilient and support a wider range of wildlife.

Water Wisely

Water deeply and only when your plants need it. A thorough soaking encourages deeper root growth. Soaker hoses or hand watering can help direct water where it is needed while avoiding unnecessary wetting of foliage.

Tips for Efficient Watering

• Water in the morning or early evening to reduce evaporation.
• Water deeply rather than frequently and lightly.
• Add compost or mulch to help retain moisture.
• Avoid overwatering, which can reduce oxygen in the soil and contribute to plant disease.

For lawn watering, follow current regional watering restrictions.

Not every insect in your garden is a pest. Many insects are beneficial and help control organisms that damage plants. Before treating a pest problem, identify the pest and determine whether action is actually necessary.

Try Non-Chemical Approaches First

1. Improving growing conditions with compost, mulch, watering or appropriate pruning.
2. Hand-picking insects.
3. Removing weeds.
4. Pruning diseased plant material.
5. Using physical controls such as sticky traps.
6. Encouraging beneficial insects.

Healthy plants and lawns are generally more resilient to pest problems.

Beneficial Insects

Beneficial insects can help naturally control garden pests. Examples include:

• Ladybugs
• Lacewings
• Ground beetles
• Hover flies
• Wasps
• Spiders

Ladybugs

Ladybugs feed on aphids and other small, soft-bodied insects.

Lacewings

Lacewing larvae are predators that feed on pests such as aphids, thrips, scale insects, moth eggs, small caterpillars and mites.

Ground Beetles

Ground beetles are active predators that feed on pests including slug eggs, snails and root maggots. Protecting beneficial insects can reduce the need for pest-control products.

Regular inspection and maintenance can help identify problems early. Early identification makes it easier to address problems before they become widespread.

Prune Properly

• Pruning can improve air circulation and allow more light to reach plants. 
• Use clean cuts and appropriate pruning techniques to reduce opportunities for pests and disease.
• Clean and disinfect gardening tools when moving between plants to help prevent the spread of disease.

Monitor Your Plants

Inspect plants regularly for signs of problems, including:

• Discoloured leaves
• Misshapen shoots
• Leaf spots
• Insect activity
• Other unusual growth

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 (PDF) and the Knotweeds Factsheet (PDF).

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 & 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 (PDF) or the Invasive Species Council of BC's Giant Hogweed Factsheet (PDF).

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

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 (PDF).

Helpful Resources

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

• Invasive Species Council of Metro Vancouver (ISCMV)
• Metro Vancouver Best Management Practices Guides
• Invasive Species Council of BC (ISCBC)

The City of New Westminster regulates pesticide use for cosmetic purposes on outdoor plants through its Pesticide Use Bylaw.

Pesticide Use Bylaw

The City's materials explain that the bylaw restricts the use of pesticides for cosmetic purposes on residential and public land and applies to homeowners, the City and landscape professionals. Pesticides include products used to control:

• Weeds, such as herbicides
• Insects, such as insecticides
• Fungal diseases, such as fungicides

Some products are permitted under the City's requirements.

Avoid Unnecessary Pesticide Use

Smart gardening focuses on prevention and non-chemical approaches first. If you are considering a pesticide, check the City's current requirements and permitted-product information before using it.

Important: Products that combine fertilizer and herbicide, such as "Weed and Feed" products, contain pesticides and may not be permitted under the City's requirements.

If You Need to Treat a Pest Problem

Use non-chemical methods first whenever possible. If a pesticide is necessary, identify the pest and choose a product that is permitted for the intended use. The brochure identifies examples of permitted pesticide ingredients for particular situations, including:

Always check the current City requirements and carefully follow the product label for dosage, application method and treatment intervals. If hiring a lawn or garden-care company, ask whether the company is appropriately accredited or offers an organic landscaping program.

Safe Pesticide Disposal

Do not pour leftover pesticides down a drain or place them in the garbage. Domestic pesticides are considered hazardous materials and should be disposed of through an appropriate hazardous-material collection service. Empty pesticide containers should be disposed of according to current disposal requirements and should not be placed in recycling unless specifically accepted.

For current disposal information, contact the appropriate recycling or hazardous-material disposal service.

A healthy, dense lawn is naturally better at resisting weeds and pests.

Choose Suitable Grass

Choose grass species or cultivars that are suited to local growing conditions. A suitable grass will be better able to tolerate local conditions and compete with weeds.

Water Your Lawn Wisely

• A lawn generally requires about 2.5 cm of water per week when rainfall is insufficient.
• Water in the early morning or evening and follow current Metro Vancouver watering restrictions.
• Avoid overwatering. Too much water can reduce oxygen in the soil, encourage disease and result in shallow roots.

Mow Smarter

Keep mower blades sharp and avoid cutting grass too short. Allow grass to grow to approximately 8 cm before mowing. Slightly longer grass can:

• Shade the roots
• Help conserve soil moisture
• Crowd out weeds
• Improve lawn resilience

Leave Grass Clippings

Consider grass cycling by leaving grass clippings on the lawn after mowing. Grass clippings can return nutrients to the soil and may provide a significant portion of the nitrogen the lawn needs, reducing the need for additional fertilizer. Leaving appropriate grass clippings on the lawn does not cause thatch buildup.

European Chafer

The European Chafer beetle is a common lawn pest in the New Westminster area. The grub is the most damaging life stage, feeding on grass roots from summer through the following April. Birds and skunks may also damage lawns while feeding on the grubs. The City of New Westminster recommends beneficial nematodes as a management option. These microscopic organisms attack the grubs and are best applied to lawns from mid-July to mid-August. In 2019, the bacteria Bacillus thuringiensis var. galleriae (Btg) was registered as a biological control agent for European chafer beetle. Available in local garden centers, the ease handling and application will result in better control for most homeowners than nematodes . 

Maintaining a healthy lawn can help reduce the impacts of European Chafer beetle. To learn more, visit the BC Ministry of Agriculture and Food Management European Chafer Guide.