Noxious plants

Sightings of giant hogweed and other invasive species should be reported both to the province and the municipality.

Poison ivy, ragweed, and giant hogweed cause skin irritation and sometimes more serious symptoms. Seek medical attention if exposed.

Many plants are poisonous to humans when ingested or if skin comes in contact with plant chemicals. Contact with the sap oil of certain plants can cause an allergic skin reaction.

Poison ivy

Poison ivy is widespread in Ontario, though more concentrated in southern regions. Poison ivy is a perennial plant with distinctive three-leaf stalks. The plant produces oil in its roots, stem, flowers and leaves, which cause dermatitis (skin inflammation) when the oil comes in contact with exposed skin. If contact with poison ivy occurs, thoroughly wash exposed skin with soap and water, and seek medical attention.


Common ragweed is appearing in Ontario, and the pollen produced by this broad leaf weed is a common allergen that causes hay fever and dermatitis. Ragweed pollen is largely distributed via plant disturbance and wind, which is known to carry the pollen hundreds of kilometres.

Giant hogweed

Giant hogweed is an invasive species that grows up to 14 feet high. The large saw blade-shaped leaves produce a watery sap that causes skin to become hypersensitive to sunlight. Sap exposure can occur from contact with the leaves or stem of the plant and can produce a painful skin inflammation or temporary blindness if eye contact occurs.

If skin contact occurs, remove the sap as quickly as possible without spreading it and wash the affected area thoroughly with soap and water. Then, wash your hands and cover the affected area to avoid exposure to sunlight. Seek medical attention. A reaction can occur up to 48 hours after contact.

If your eyes come in contact with the sap, rinse your eyes thoroughly with clean water for 10 minutes and wear dark sunglasses to avoid exposing your eyes to sunlight. Seek medical attention as soon as possible.

How do I report giant hogweed?

Report all giant hogweed and other invasive species sightings to Ontario’s Invading Species Awareness Program by calling the invading species hotline at 1.800.563.7711.

Please report sightings of giant hogweed in the City of Greater Sudbury to Environmental Initiatives at 705.674.4455, ext. 4397 or by dialing 311.

If you have a question or concern regarding noxious plants, you can submit your question or concern electronically or call Public Health Sudbury & Districts at 705.522.9200, ext. 464 (toll-free 1.866.522.9200).

This item was last modified on May 14, 2024