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Invasive Species We Removed

During Our Invasive Species Removal Events

2022 Invasive Species Removal

2023 Invasive Species Removal

2024 Invasive Species Removal

Garlic Mustards (2022—2024)

Garlic mustard (Alliaria petiolata), an edible herb native to Europe, was brought to North America in the early 1800s and first reported in gardens of Toronto in 1879. Garlic mustard is one of Ontario’s most aggressive forest invaders. Its roots produce chemicals that prevent the growth of other plants and grasses. These same chemicals also affect the growth of arbuscular mycorrhizal fungi (AMF), a fungi that that help other plants to absorb nutrients and water. In forests abundant with Garlic Mustard, the reduced amount of AMF inhibits the growth of native tree seedlings and plants. Garlic Mustard is also a host to several viruses such as cucumber mosaic virus, cabbage black ringspot virus, and turnip mosaic virus. These viruses may affect other horticultural plants and agricultural crops.


Dog-Strangling Vine (2022, 2024)

Dog-strangling vines are perennial plants (ie: live for more than 2 years) that have vines that can grow up to 2 meters long by wrapping onto or "strangling" nearby trees and plants. They often grow in sunny areas but can also be found under light shade. Introduced as an ornamental plant for the early settlers, dog-strangling vines release allelopathic chemicals that block sunlight for smaller plants. Therefore, dense clusters of these invasive plants create a negative change in the habitat for wildlife. Dog-strangling vines also endanger native insects such as monarch butterflies because these butterflies mistake the dog-strangling vine for milkweed and lay their eggs on it, only for them to starve.


-   THE MID-1800s: First introduced to North America from Eastern Europe.

-    1897: First record of the dog-strangling vine in the United States.

-    THE 1900s: Dog-Strangling vines spread to southern Ontario.

-    PRESENT: Dog-strangling vine continues to expand its range and spreads to even more southern parts of Quebec.


Common Burdock (2023—2024)

Common Burdock (Arctium minus), a biennial plant native to Europe, was first reported in North America in 1638. Common Burdock proagates by seed; during its lifespan, each plant can produce 6,000 to 16,000 seeds. Seeds are spread in the form of clinging and prickly burrs; each burr contains up to 40 seeds. These burrs can attach themselves to the skins of wild and farm animals and remain on these animals for several weeks, causing injuries such as blindness and skin irritation. Burrs can also trap small animals such as birds and bats, leading to disruptions in the ecosystem. Furthermore, Common Burdock damages the quality of the wool produced by sheep, and cattle that consume Common Burdock produce milk with a bitter taste.


Motherwort (2024)

Motherwort (Leonurus cardiaca), a perennial herb native to Asia and southeastern Europe, was introduced by colonists into North America. It is invasive in wooded areas and less shaded areas, especially on the edges. Motherwort can spread rapidly by reseeding and by sprouting vegetatively via rhizomes, and they often form large and dense colonies. 

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