Terrestrial Invasive Plants

This information was provided by the LCPOA Environment Committee, December 2020.
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Invasive Phragmites

Invasive Phragmites

​​Phragmites are tall purple to brown grasses topped with long silky seedheads that can be found in shallow water and ditches throughout Ontario. Unfortunately, an invasive form, the European Common Reed (Phragmites australis) has been spreading quickly throughout Ontario by seed dispersion and spreading roots or fragments and is now outcompeting native plants for nutrients and water.

​Frequently Asked Questions (FAQ's)

1. How can we recognize this invasive form?

The invasive form can be distinguished from the native as the stem is pale yellow or tan, not reddish brown, and it is substantially taller reaching up to 5 metres in height. The seed head of the invasive plant is longer and denser. Phragmites australis also form much denser stands as they can release toxins into the soil to kill surrounding plants.

2. What are the dangers of letting this plant spread?

​These invasive plants create an environment that is inhospitable to wildlife and out compete natural food sources. Dead stalks also increase fire hazards.

Photo shows native seed head at top and invasive on the bottom.  Photos from https://www.ontario.ca/page/phragmites-fact-sheet

Common Mullein

Common Mullein www.ontariowildflowers.com

This fast spreading blue-green woolly-leafed biennial plant has recently been popping up along our roadsides and in disturbed open areas on our properties. During its first year of growth, the large leaves form a soft low-lying fuzzy leaved rosette. In the spring of the second year, the plant develops a tall stem that can grow to more than 1.5 m in height. The top portion of the stem develops yellow flowers that have a faint, honey-like odour.

Frequently Asked Questions (FAQ's)

1. How did this non-native plant first arrive in North America?

​European settlers into the eastern U.S first introduced this plant in the 1700s as a fish poison, and later it was planted throughout the west as a medicinal plant with its flowers and stamens being used as an herbal remedy mostly for respiratory issues.

2. Why is it considered invasive?

This plant is adaptable to a variety of environments and can quickly overtake native herbs and shrubs in meadows and forest openings. In the second year of its life one plant can produce up to 180,000 seeds, which can survive in the soil for 100 years.

3. What can we do to hinder the spread?

Due to shallow roots both first and second year plants can be easily hand pulled. It is quite fun and satisfying to be able to pull such a large stalk so easily with one hand! If seeds or flowers are present, they need to be bagged and disposed of in a landfill.

4. What other invasive plants are found in Ontario forests?

More information on invasive land plants in Ontario such as Dog-strangling vines, Buckthorn, and Purple Loosestrife can be found at:
 http://www.invadingspecies.com/4-terrestrial-plant-resources/