Natural Environment
Invasive Species

What is an invasive species? What is a noxious weed?

Invasive species are those that have been introduced from outside of their native region, and become a threat to local biological diversity. Hundreds of alien organisms have been introduced; some intentionally through activities such as horticulture or aquaculture, but others have been introduced accidentally. Not all introduced species are considered invasive or harmful because they are not spreading. However, some introduced species will show a lag period before they become invasive and threaten native species. For this reason, and especially since the climate is changing, we should use native species wherever possible and limit any new introductions.

Most invasive species that we deal with in Saanich are plants, but there are hundreds of other equally damaging invasive animals in our region that are competing with native or indigenous species. Some well-known examples are English House Sparrow, European Starling, Eastern Cottontail, Grey Squirrel, American Bullfrog, Gypsy Moth, and Winter Moth.  Some invasive species that may surprise you include: Muskrat, Pacific Oyster, Brown Trout, and Smallmouth Bass.

Another term that is often used for invasive plants is noxious weed. The Municipality of Saanich has a Noxious Weed Bylaw that is primarily reserved for plant species that are capable of inflicting agricultural loss or ill health on people.

Why Should We Be Concerned?

Invasive species aggressively expand their range at the expense of existing native biological diversity. They have no natural controls such as predators, parasites, or diseases to keep them in check. Globally, invasive species are second only to habitat loss as a serious threat to biological diversity and are known to have been responsible for species extinctions.  The rate of new introductions is increasing rapidly, and, if left unchecked, invasive non-native species can replace entire populations of native flora and fauna. The effect of this displacement cascades throughout the whole food web and ecosystem. Some invasive organisms can have immense agricultural impacts and can be detrimental to human or animal health. Any benefits of invasive species, such as providing food, habitat or barriers, can be better provided by suitable native species.

In Saanich, one of the biggest threats to natural ecosystems is the spread of invasive, non-native plants. For example, here is a list of possible negative impacts of introduced plants:

What is Saanich Doing?

Invasive species have devastated many natural areas in Saanich and in the Capital Regional District. It can seem like a daunting task to try to control them, but with your help, these plants can be prevented from gaining further ground in specific locations. The Municipality of Saanich is trying to control invasive plant species by providing on-the-ground removal with Parks staff and also partnering with local community groups that are actively controlling invasive species in their neighbourhoods. Regular work parties happen in many of our Saanich parks, and we provide help with labour, materials, clean-up and disposal, as well as management of the activities and other support for the wonderful volunteers. Saanich also provides invasive species education, advice on proper removal, bylaw enforcement, and waste drop-off locations.

Saanich’s Garry Oak Restoration Program (GORP) restores Garry oak ecosystems, and spends much of its resources removing invasive plants such as Scotch broom. There are also many community groups, devoted to protecting natural areas in their neighbourhood that spend countless hours cutting Himalayan blackberries or pulling Daphne laurel, Scotch broom and English ivy. Please contact us if you would like to become involved in a local restoration effort.

Saanich’s Noxious Weeds Bylaw

Through the Noxious Weeds Bylaw, property owners in the Municipality of Saanich can be required to remove “bylaw listed” noxious weeds, or any other invasive plants that are likely to spread or become a nuisance to other property in the vicinity. Invasive species are those that have been introduced from outside of their native region, and become a threat to local biological diversity, while Noxious Weed is a term primarily reserved for plant species that are capable of inflicting agricultural loss or ill health on people.

The specifics of the bylaw can be found at the following link:

Saanich Noxious Weed Bylaw

Plants on Saanich’s Noxious Weed List:

Invasive Plants Now Established in Saanich

Although a number of invasive plants are well-established in Saanich, it is possible to make a difference for native ecosystems by managing the spread of certain species. Individual land owners can assist by controlling invasive plants on their properties. The listed brochures provide information on how you can help to control some of the invasive plant species that are of concern in Saanich.

Invasive Plants Brochure  (PDF 1.0 MB)  Includes information about English ivy, Scotch broom, English holly, Himalayan blackberry, and Daphne laurel

What’s New?

Recent Invaders:

The following plants are more recent newcomers to Saanich, or are particularly toxic and are considered high priority for management to control their spread in the area.

Click on a photo below to learn more about these plants.

Giant hogweed                                         Knotweed
Yellow flag iris                                         Poison hemlock
Garlic mustard
	The District of Saanich is asking the public for assistance in identifying and eradicating this particularly nasty invasive plant.  Please see the June 2009 media release.

Do not compost any of these plants: please dispose of invasive plant material as outlined below.

If you think you see any of these invasive plants in a park or public land in Saanich, please contact Saanich Parks: 250-475-5522 or parks@saanich.ca

Please note that these are not all of the invasive plants that we should worry about. Others include, English hawthorn, common St. John’s-wort, periwinkle, butterfly bush, Cotoneaster, Portuguese laurel, reed canary grass and many other grasses.

Most importantly you can help by not planting invasive or introduced species on your property and removing them if they are already there. Inform others of the impacts that these invasive plants have on our native flora and fauna. Learn to garden with native plants which are adapted to our climate, and provide valuable habitat and food for our native fauna.

Proper Disposal and Disposal Sites

Invasive plants are proficient at spreading to new areas, so plan disposal as carefully as removal. Remove cuttings on tarps or in bags to avoid spreading seeds or leaving behind roots or stems that can take root in moist soil.

The District of Saanich is in the process of developing a protocol for handling and disposing of invasive plant species that are removed from private lands.  Please contact Environmental Services for up-to-date information on proper removal and disposal techniques. A current option is to place all plant parts in garbage bags labelled "invasive species", and take to Hartland Landfill. 

Other non-invasive plant material can be composted at home or at an approved site such as the Saanich Public Works Yard. Garden waste dropped off here is composted and used locally for agricultural soil amendment. 

Saanich Garden Waste Disposal at the Public Works Yard

1040 McKenzie Avenue
(enter off Borden)
For hours of operation: 250-475-5595

Native Plant Gardening Links:

The Garry Oak Gardener’s Handbook

Important Invasive Species Links:

Saanich Noxious Weed Bylaw

Invasive Plant Council of BC

Horticulture Brochure (Invasive Plant Council of BC)

Coastal Invasive Plant Committee

Alien Species in British Columbia (Government of BC)

E-Flora BC

The Greater Vancouver Invasive Plant Council