City of Ottawa to spray 1,200 km of roadways with herbicide to battle wild parsnip this spring

Wild Parsnip Caution signs along Akerson Road around South Kanata July 13, 2019.

The City of Ottawa says it will begin spraying herbicides next week to tackle the growth of wild parsnip, an invasive plant that can cause harm to humans and animals that come into contact with it.

Wild parsnip plants secrete oils that can cause skin to burn and blister when exposed to sunlight.

The city says this year’s wild parsnip strategy will come into effect starting Monday. Approximately 1,200 kilometres of roadside around the city, and several parks will be treated with herbicides and hand-pulling of plants where smaller infestations are found. Council approved $298,000 in the 2025 budget for dealing with wild parsnip this year.

Roadside grass cutting will begin in early June, and additional herbicide application may be considered again for the fall, the city says.

“The goal of the program is to reduce the growth of wild parsnip in highly infested areas while ensuring that environmentally sensitive areas and public safety are not adversely impacted,” said Alain Gonthier, general manager of Public Works, in a memo Wednesday.

The city says Clearview and Navius FLEX herbicides will be used on roadways. Clearview and glyphosate herbicides will only be used in parks where necessary.

Rural residents who did not wish to have the roadside adjacent to their property sprayed were given the option to opt out of the program by informing the city. Any resident who opts out must manage any wild parsnip infestations adjacent to their property themselves. An opt-out letter was sent to eligible residents in April. Tuesday was the deadline to apply to opt out of the program.

What is wild parsnip?

Wild parsnip is an invasive plant that is increasingly common within the City of Ottawa in areas of uncultivated land, roadside ditches, nature trails, as well as on and surrounding rural and residential properties, the city says.

“Wild parsnip is a highly branched plant, with hollow green stems. It has two growth stages: non-flowering leafy rosettes at ground level and 0.5 to 1.5 metre-tall flowering plants,” the city’s website says.

Early growth: In the first year of growth, low-growing non-flowering rosettes of leaves form with a cluster of spindly, compound leaves that resemble celery leaves.

In bloom: When wild parsnip is in bloom, usually in the second and third-year plants have tall, branched yellow flowering stalks that usually bloom in early June to late July.

Mature plant: Starting in August ‎the blooming plant will begin to turn brown and the leaves and stems will begin to dry up. This means that the toxic sap from the plant will also begin to dry up, and contact with the plant is less likely to cause a reaction.

“Seeds are flat and round. It is a biennial plant, reproducing only by seed. The seeds can lie dormant for years making it even more challenging to control,” the city says.

Avoiding wild parsnip

The City of Ottawa offers the following tips to avoid wild parsnip on pathways and in parks:

Stay on the groomed areas of parks, roadsides and pathways where there are fewer instances of wild parsnip.

When working around wild parsnip or when walking through dense vegetation, wear goggles, gloves, long pants and long-sleeved shirts.

Children should be reminded not to pick wildflowers.

If you are exposed to the plant sap, wash the contaminated area(s) thoroughly as soon as possible, and seek medical attention if skin irritation occurs.