Dense thickets of Salmonberry (Rubus spectabilis) and Thimbleberry (Rubus parviflorus) line parts of the South Beach Trail in Pacific Rim National Park Reserve . However, at this time of year they are the dramatic flower heads and leaves of Cow-parsnip (Heracleum lanatum) overshadow other plants. The large umbels are in various stages of flower and going to seed but there is no mistaking the look and celery smell of this distinctive plant.

A Member of the Carrot Family

Cow-parsnip is a member of Apiaceae (Carrot family), a group that includes the very similar looking (but much taller) Giant Hogweed (H. mantegazzianum). Cow-parsnip can reach heights of 3 metres while Giant Hogweed towers up to 4.5 metres tall! Seabrooke Leckie provides an excellent profile of Giant Hogweed over at the Marvellous in Nature and Hugh over at Rock-Paper-Lizard connects the plant to Peter Gabriel and Genesis’ “Return of the Giant Hogweed.”

While this nasty invasive grows in many places in Vancouver Island and is on British Columbia’s Invasive Plant Watch, it does not grow on the South Beach Trail. However, like Giant Hogweed, Cow-parsnip sap contains furanocoumarins and is also phototoxic (although somewhat milder – I’ve handled the stems without incident and I wouldn’t think of doing that with Giant Hogweed). The fascinating chemical process that causes the phytophotodermatitis is described in detail at Watching the World Wake Up. The sap causes extreme sensitivity to ultraviolet light and exposure to the sun results in a blistering rash.

Identifying Features

Everything else about Cow-parsnip is also over-the-top. The leaves areare the size of large dinner plates (between 10 – 40 cm across) and divided into three segments. Cow-parsnip leaves resemble a maple leaf on steroids. The base of the leaf stalk is sheathed and inflated. The white flowers are small but form a large umbrella-like cluster – each of these flowers produces a sunflower-like seed. The plant grows in profusion in wet areas like stream banks, ditches, marshes and wet meadows.

First Nations peoples on the coast of British Columbia ate this plant as a green vegetable, peeling the young stalks and stems and eating them raw before the plant went to seed. Caution. It would be unfortunate to confuse this plant with Giant Hogweed, deadly Poison Hemlock (Conium maculatum) or any of the other poisonous and similar looking members of Apaiceae. Maybe it would be better to admire these beautiful native plants with an ounce or two of respect!