The County of Renfrew would like to remind the public about wild parsnip.
Staff continues to receive inquiries about the presence of wild parsnip on public and private property and further calls are expected in 2017. Wild parsnip (Pastinaca Sativa) is an invasive plant that is increasingly common within the Renfrew County in areas of uncultivated land, roadside ditches, nature trails, as well as on and surrounding rural and residential properties. Wild parsnip may pose a health risk to humans.
The plant sap contains chemicals that may cause skin and eye irritation and make the skin prone to burning and blistering when exposed to the sun. The blisters typically occur one to two days after contact with the plant. This can result in long-term scarring of the skin. The best way to avoid contact with wild parsnip is to become familiar with what the plant looks like so you do not accidentally come in contact with the plant.
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 yellow flowering plants. 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. Second- and third-year plants have tall, branched flowering stalks that usually bloom from early June to late July.
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. Once the plant is completely dry the seeds will fall to the ground. 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.
County staff will be working within the Integrated Pest Management Plan to educate workers and the public, map and reduce hazardous plants on county-owned propertied this growing season.
“Residents are encouraged to become familiar with wild parsnip and its effects and should take measures to protect themselves. County staff continue to respond to reports of wild parsnip and other noxious plants,” said Jason Davis, area weed inspector for the County of Renfrew.
Strategies to remove wild parsnip include:
Digging the root up: Residents that have a small infestation in a yard or garden (fewer than 100 plants), or who do not want to use pesticides, can dig out as much of the taproot as possible with a sharp shovel or spade. Follow-up digging will be required every few weeks to deal with re-growth (if the taproot was not completely removed) or plants are missed. DO NOT burn or compost wild parsnip plants that have been cut down or dug up. Plants and roots that have been removed should be placed in a dark plastic bag and placed in the sun if possible away from areas where they can be accessed by children or pets. After the wild parsnip plant has been left in a black bag for one to two weeks in the sun, it can be collected through your normal waste collection as garbage, not as leaf or yard waste. Wear goggles and protective clothing when digging.
Targeted mowing: Mowing can be effective if begun just after peak blooming, but before the seeds set in the late summer or early fall. Cut plants will likely re-sprout after mowing, so it is important to combine mowing with other control methods such as bagging and removing the plants, especially those that are flowering and spot spraying with an approved herbicide. Be especially careful when using mowers, weed whips, mechanical string trimmers as they can spray users with sap and bits of the plants, leading to redness and sometimes hundreds of blisters on exposed skin. Wear goggles and protective clothing when mowing.
Use of herbicides: When a weed such as Wild Parsnip is declared a noxious weed residents are able to purchase herbicides to control it. This is not considered a cosmetic use of pesticides because this plant can pose a risk to people. For more information please visit