SEUMAS Bates was just trying to do his mother a favour, but soon after clearing underbrush at the rear of their West Vancouver home, sap coated his arms and the kind deed turned nasty.

The next day, the 14-year-old Sentinel secondary student woke up with red spots on his skin. "I thought at first it was a reaction to food or something," he said.

What started out as minor, soon became worrisome. The next day the splotches reddened, and after two days they became large blisters of yellow puss, some three inches high.

"It felt something like a chemical burn," Seumas explained, "it was very painful. The pain seemed to get worse and worse throughout the day."

The culprit behind Seumas's injuries was later identified as hogweed, a plant growing in the family's British Properties backyard.

Hogweed is usually relatively easy to identify, growing up to five metres tall, with dark green leaves and clustered heads of white flowers. The plant that injured Seumas, however, was a smaller, less mature plant. Nevertheless, it still carried the weed's noxious properties. "It was actually very short, maybe ankle height. Not very tall at all. I didn't think much of it. I thought it was a plant that we call in Britain cow parsley."

Seumas's mother, Stephanie Marian, was the one who identified the hogweed. "I had done some research and gone on the Internet . . . so I put two and two together. I realized that maybe he had been in contact with something, and I went down to look."

Even when not fully mature, hogweed's hollow stalks with purple spots can be a dead giveaway. Sadly, these stalks are also often picked up by children and used as telescopes and swords. When sap gets in contact with the eye, it can cause permanent blindness.

Because of their sometimes dangerous properties, Agriculture and Agri-Food Canada have set up a website called weedinfo.ca where the public can upload pictures and have weeds identified by experts. The Invasive Plant Council of B.C. has a phone line where residents can report suspicious weeds at 1-888-WEEDSBC. More information on invasive plants can be found at www.invasiveplantcouncilbc.ca.

Residents in Toronto, where there has been a rash of hogweed sightings this summer, have been encouraged to take care in removing plants. Eye and hand protection is especially important, but if in doubt, hiring a lawn care professional is advisable.

If untreated, hogweed burns can become black and cause permanent scars. Seumas found a North Shore homeopath, Susan Drury, who had experience with his unique injuries. Drury herself had suffered hogweed burns while travelling in Ireland a few years ago, and ended up in the hospital.

"She was absolutely fantastic," said Seumas's mother. Drury was able to match Seumas's symptoms with homeopathic remedies, which greatly reduced his pain.

Seumas has been doing well. "The sensitivity has actually dulled on the scars," he said, a month after the incident. "It doesn't hurt anymore."

He is optimistic about his recovery, "I think the scars will disappear eventually."