Giant Hogweed vs. Native Cow Parsnip

Giant Hogweed (Heracleum mantegazzianum), native to southwestern Asia, is a well-known invasive plant, frequently pictured towering over someone in heavy-duty protective equipment. Not only is this plant invasive, it has the potential to cause severe burns and blisters on the skin due to the presence of its toxic sap.

Giant Hogweed (SSISC

Because of its popularity as an invasive and noxious weed, people are quick to report sightings of Giant Hogweed. However, did you know that Giant Hogweed has a native look-alike?

Cow Parsnip (Heracleum maximum) is native to North America (including the Sea to Sky!) and shares certain characteristics with Giant Hogweed. For instance, it too contains a toxic sap.

The toxic sap that exudes from both plants hairs contains furanocoumarins which sensitize the skin to U.V. radiation. If this clear and watery sap gets on skin, exposure to sunlight can cause severe burns. However, the burns caused by Cow Parsnip are not as severe as those caused by Giant Hogweed.

The main distinguishing features between Cow Parsnip and Giant Hogweed is the overall size of the stems and flowers, as well as the shape and size of the leaves.

Learn how to identify these two plants, and keep yourselves safe from toxic sap!

Giant Hogweed

Stem: 2-5m tall, 10cm in diameter; coloured with reddish-purple spots; stiff bristles.

Flowers: Small white flowers grouped together to form a wide umbrella-like shape (umbel) that spans 50cm across.

Leaves: Up to 1.5m wide, and 3m long; similar in shape to a maple leaf or hand, deeply incised.

Cow Parsnip

Stem: 1-3m tall; lightly coloured; deep ridges; fuzzy hairs.

Flowers: Small white flowers grouped together to form a wide umbrella-like shape (umbel) that spans 10-20cm across.

Leaves: 60 – 75 cm wide, 10-40cm long; similar in shape to a maple leaf or hand, divided into 3 segments.

Learn to identify the difference between Giant Hogweed and Cow Parsnip. Steer clear from their leaves and stems.