Watch for these invasive plants

Common tansy.
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The Nature Conservancy of Canada and the Canadian Council on Invasive Species are urging Albertans to watch for five invasive species and remove them if spotted on their property:

Common tansy: Has yellow, button-like flowers and can grow 1.5 metres tall. It impacts stream banks and native grasslands and outcompetes native plants. It also produces a toxic compound harmful to cattle and wildlife.

Yellow flag iris: A wetland plant with pale-yellow flowers that have six segments (three downward-facing petals and three erect petals) with delicate purple flecks.

Purple loosestrife: Still sold in some places as an ornamental plant, it crowds out most native vegetation and creates near monocultures. A single plant can produce over two million seeds each year.

Leafy spurge: Has yellow-greenish flowers, and its leaves and stems have a white, milky sap. It spreads quickly in open areas and threatens habitats, such as tall grass prairie.

Common toadflax: Has smooth green stems and numerous hairless leaves which are wide and pointed at both ends. Densely spaced flowers are bright yellow with an orange spot like snapdragon flowers, to which they are related.

For detailed descriptions and photos, go to the ‘invasive species gallery’ at

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