Invasive plants, also known as noxious weeds are non-native plants that have been introduced to B.C. Without their natural predators that help keep them in check in their native habitats, these alien plants grow very aggressively and pose a threat to our natural ecosystems, biodiversity, humans, wildlife and the economy. One such invasive plant is Giant Hogweed, and it is often mistaken for a local native plant called Cow Parsnip.
The two plants do look very similar to each other, but only Giant Hogweed is classified as a provincially noxious invasive weed and has phototoxic stems and leaves containing a poisonous sap that makes skin sensitive to light often leading to serious burns and painful blisters (note: Cow Parsnip can also irritate the skin but to a much lesser extent). Protective clothing should be worn when handling either plant and wash any skin that has been exposed with soap and water then keep skin covered.
So how can you tell the difference between the two and what should you do?
Height: Cow Parsnip fully grown tops around seven feet, while Giant Hogweed can reach heights of 14 feet or taller.
Stems: Cow Parsnip stems are green and ridged with fine white hairs. Giant Hogweed stems are green but with purple/reddish splotches and much coarser white hairs.
Leaves: Cow Parsnip leaves are similar to that of a maple leaf, while Giant Hogweed leaves have visible knife-like serrated edges (see pictures).
Flower Cluster: Cow Parsnip has up to 30 rays per flower cluster, while Giant Hogweed can almost double that and have 50 rays. Rays, are the stems of the flowers protruding from the main stem of the plant (see diagram).
For more information on identification, removal and disposal of Giant Hogweed, please view or download the National Factsheet with full colour pictures. Available online, find a link to this factsheet at http://cccipc.ca/index.php/about-us/links/ or email info@cccipc.ca for a copy.
To report invasive plants in the CRD please call 1-800-665-1636, in BC to 1-888-WEEDS-BC or online to www.reportaweedbc.ca (or download the free phone app). For more information on other invasive plants in this region please visit the Cariboo Chilcotin Coast Invasive Plant Committee website at www.cccipc.ca or call 250-855-WEED (9333).
The CCCIPC gratefully acknowledges the financial support of the Province of British Columbia.
Jessica Knodel is the CCCIPC co-ordinator.