Wild Parsnip is listed as Category 3 which is defined as “exotic species that are moderately invasive but can become locally dominant when the proper conditions exist. It is recommended to control plants where necessary and limit their spread to other areas.” Wild Parsnip is a hazardous plant as the sap can cause a phytophotodermatitis reaction if it comes into contact with a person’s skin. A phytophotodermatitis reaction happens when certain plant chemicals cause the skin to become inflamed following exposure to sunlight. It is also listed on the list of Noxious Weeds of Ontario.

Tree of Heaven is l isted as Category 2 invasive species which is defined as “exotic species that are highly invasive but tend to only dominate certain niches or do not spread rapidly from major concentrations. It is recommended to control plants where necessary and limit the ir spread to other areas.”

Management Methods:

Generally speaking, there are three (3) methods for removing these invasive species. Those methods include: hand removal, machine cutting, and/or spraying. In looking specifically at the east bank of Little River, not all of these three methods are recommended due to the location of the plants.

Hand Removal

Due to the size and landscape of the area, hand removal would be difficult and time-consuming. The invasive species are growing on a rocky embankment that runs alongside Little River. It is unsafe for staff to be on the embankment as they could easily slip into the river. The area is also quite large so removing by hand would be time consuming. This method would be recommended for this location with enhanced safety measures.

Machine Cutting

This would involve bringing in a large piece of machinery to flail mow the area to cut down the invasive species. Because of the rocky embankment, a normal mower would not be appropriate and the Parks department’s roads ide ditch cutter would be required. Taking a mechanical cutting approach could result in the broadcast of seeds and further spreading of the invasive species. There is also the possibility of mowing desired plant species. This method would not be recommended.

Spraying

The last option involves spraying an herbicide. Broadcast spraying would eradicate all plant life it comes in contact with which is not something Administration would recommend. There is also concern of the spray being washed into the river, which could have a negative effect. Lastly, there is a possibility of endangered plant species in the area which would restrict this method of spraying. Targeted herbicide application where the herbicide is applied directly to the desired plant would be recommended.