If you are out enjoying nature this summer please pay close attention to your surroundings: This plant is found all across Canada.


hogweed (Heracleum mantegazzianum)General Information: Giant hogweed is a perennial member of the carrot family originally from Asia.

It was introduced in Nova Scotia as an ornamental garden plant. This plant has the potential to readily spread from gardens along roadsides, ditches and streams invading native habitats.

Giant hogweed closely resembles our native cow parsnip which is also a member of the carrot family. Its size makes it a distinctive plant, growing up to over 5 meters tall at maturity under ideal conditions. The white flowers, resembling those of Queen Anne’s Lace, form a large umbrella shaped head, that can be 1 meter or more wide.

Distribution: During the 1980’s this plant was present in the garden of the Alexander Graham Bell Museum in Baddeck. It seems likely that it was intentionally planted there. Prior to July 1,2010 there were several known locations in Nova Scotia, including Jollimore, Purcells Cove,Halifax, Dartmouth, Wolfville, Grand Pre, Sydney and Baddeck.

More recent confirmed plant locations are Kentville, Sheffield Mills and Truro. Biology: Seeds may take several years to germinate and are viable in the soil for up to 15 years. Once the seed has germinated, it takes 2-5 years of growth before the plant produces flowers. During the first year, the plant produces a rosette of leaves to 1 meter high. As the plant grows a large taproot, thick hollow stems and large deeply lobed leaves are formed. The lower stems of the plant are covered with reddish-purple flecks. The stems are covered with stiff hairs that are filled with sap. Sap may collect in the hollow stem bases.Giant hogweed flowers only once in its lifetime. Once the plant produces seed it then dies. Each plant can produce up to 100,000 winged seeds (typically 50,000) that can float for 3 days before becoming water logged and sinking. The seeds are also spread by wind but can travel much longer distances via water transport in ditches and streams.

Health Concerns: The clear watery sap of giant hogweed contains irritating sap that can cause severe dermatitis. Ultraviolet radiation activates compounds in the sap resulting in severe burns when exposed to the sun. Symptoms occur within 48 hours of contact and consist of painful blisters. Purplish scars may form, and can last for many years. Eye contact with the sap may cause temporary or permanent blindness.

In the event of any direct exposure/contact to the sap of this plant the IWK RegionalPoison Centre should be contacted at:1-800-565-8161First Aid Instructions:* Wash the affected skin IMMEDIATELY and thoroughly with soap and water.*

Affected skin should be covered to avoid exposure to any sunlight for a MINIMUM of 48 hours, avoidance of any sun exposure within 48 hours of exposure lessens the severity.*

Ocular exposure: requires immediate and thorough (20 to 30 minutes) eye flushing with lukewarm water. A UV-absorbing wrap should be used around sunglasses for 24 hours after exposure to decrease the potential of ultra violet sunlight contacting the eye.*

Continued use of sunscreen is recommended for up to 6 months after exposure as a MINIMUM.* Clothes, tools, and anything that contacted the plant sap should be washed, ensuring that they cannot spread further contamination.

Seek Medical Attention for Confirmation and/or Treatment if you notice:* Signs of burns, infection and/or blistering.*

Removal: There is no government funded program to remove this plant from private property. It is highly recommended that private landowners hire a professional landscaper to remove theplant to ensure safe procedures are followed.‚Mechanical: Wear protective clothing, including gloves, long sleeve shirts, pants, and eye protection. Wash immediately with soap and water afterwards.