What is an Invasive Species?​

An invasive species is a plant, insect or animal that causes damage to the environment, economy or human health in a new region where it is not native. They outcompete native plants for space, food, or other resources. Inv​asive plant species can be difficult control due to their natural aggressiveness, high rate of reproduction, and lack of natural predators in the environment.

These three invasive species, threatening the Town of Aurora are regulated as a restricted species under the Ontario Invasive Species Act, 2015.

EUROPEAN COMMON REED (Phragmites australis subsp. Australis)

Phragmites 1.jpg
Photo: Pond on Leslie Street is being encircled by invasive phragmites.

Photo: This open space at Bayview and Wellington has been overwhelmed by invasive phragmites.

ORIGIN:  Plant is native to Eurasia; first introduced into North America in the late 1800s.

IMPACTS: Phragmites tends to become the dominant species in a variety of habitats, due to its dense growth both above and below ground and its ability to release toxins from its roots into the soil to hinder the growth of and kill surrounding plants.

JAPANESE KNOTWEED (Fallopia japonica)

Japanese Knotweed.jpg
Photo: A large outbreak of Japanese knotweed at Bloomington and Bathurst.

IMPACTS: Commonly invades disturbed areas with high light, such as roadsides and stream banks. Reproduction occurs both vegetative (rhizomes) and seeds, making this plant extremely hard to eradicate.

DOG-STRANGLING VINE (Cynanchum rossicum)

Dog-strangling vine.jpg
Photo: Climbing up a fence on Industrial Parkway South, these well-seeded vines are just a small part of a substantial outbreak north of the Sheppard's Bush soccer fields.

IMPACTS:  Forms dense stands that overwhelm and crowd out native plants and young trees, preventing forest regeneration. This is a serious concern for the conifer plantations in the York Regional Forest. Leaves and roots may be toxic to livestock. Deer avoid dog strangling vine, which can increase grazing pressure on more palatable native plants. Threats to monarch butterfly populations; butterflies lay their eggs on the plant but, the larvae are unable to successfully complete their life cycle.



The Emerald Ash Borer, is an invasive insect that kills all types of healthy ash trees. It is a major threat to the health of our Regions forests.

Noxious Weeds

The following Noxious Weeds are found in Aurora and cause harm to humans:

Photo of Poision Ivy

Poison Ivy, a harmful weed that produces clusters of three leaves, it can be found along trails and wooded areas. When the sap from this plant comes in contact with the skin, it produces blisters and irritation.

 Photo of large Wild Parsnip

Wild Parsnip, often found in ditches, trails, and residential properties. When the sap from this plant comes in contact with human skin then is exposed to sunlight it causes severe burns and blisters.


Photo of Giant Hogweed 

Giant Hogweed, found alongside roads, streams and in open spaces. The sap from this plant can cause severe blisters, burns, and scars. The effects of this plant are further intensified when exposed to sunlight. Eye contact may cause loss of vision.


What can you do to stop invasive species?

  • Learn to identify these species
  • Use designated trails and keep pets on a leash to avoid accidentally spreading of these invaders
  • Learn to effectively and environmentally manage these invasive species on your private property
  • Buy native species to plant in gardens and landscaping
  • Clean all equipment thoroughly to remove seeds, leaves and mud
  • Encourage people to report any illegal importing, distribution or sale of Dog-strangling vine and Japanese Knotweed

For more information on how to deal with invasive species please visit Ontario's Invading Species Awareness Program Website.

A to Z Services: