Victoria, B.C. - That huge, exotic plant filling a corner of your garden could be a noxious, invasive weed that authorities say poses health risks to you and your family.
Giant hogweed grows up to six metres high and has leaves that can span 1.5 metres. The clusters of blooms can measure a metre in diameter and ripen into 150,000 seeds each year.
Not only does it choke out native plants, the giant hogweed's sap can cause burns to your skin or even blindness if it gets into your eyes.
"I don't know any other plant that there are WorkSafe [B.C.] regulations around," said Gail Wallin, executive director of the Invasive Plant Council of B.C.
"It has huge environmental impact. The more we let it spread before we treat it, the more money it costs."
Ironically, gardeners are partly to blame for the plant getting a foothold in B.C.
"It's planted in gardens because it's an exotic-looking species and it's certainly being traded in garden circles," said Wallin.
Victoria city staff monitor sites where the plant has been spotted, mainly on private land, said Fred Hook, environmental technician with the city's parks department.
The seeds are larger than sunflower seeds and are often carried by birds.
People confuse giant hogweed with a native plant, cow parsnip, which is similar but much smaller at maturity. Hook often gets calls from people who mistake cow parsnip growing on the Dallas Road bluffs for giant hogweed.
"I've had calls from a few other places and gone out to investigate and found it was cow parsnip," Hook said. "I'd rather go out and tell them it's not than not hear about it and find out it was."
Hook didn't know what giant hogweed was many years ago when he had a plant take hold on his Saanich acreage. The seed likely came from hay imported from Oregon, he said.
"The first year we didn't know what it was and let it grow up and flower, and it was 15 feet high," Hook said.
The seed head grew to a metre in diameter, he said.
His in-laws also had a plant and, not knowing what it was, put the seed head in the compost, where the seeds ripened. "They've been battling it on the property ever since."
Up-Island, giant hogweed grows along the banks of French Creek, near Parksville, and in Sooke, said Becky Brown, invasive plant co-ordinator with the Ministry of Agriculture and Lands.
Brown said the environmental risk is secondary to the public health risk the plant poses.
"When the sap comes into contact with skin or eyes, which are then exposed to sunlight, it generates photosensitivity and can result in blistering, burning and in some extreme cases, blindness."
Children may be tempted to use the hollow stem of the weed as a pretend telescope, and end up with sap in their eyes, said Brown. Using it as a peashooter can cause burns to the mouth or lips.
Anyone who suspects they've found giant hogweed is asked to call the provincial weed hotline at 1-888-WEEDSBC. More information is available at www.invasiveplantcouncil.ca
