If plants were capable of evil, giant hogweed would be the most evil.
In the spring of 2010, gardeners across Canada began to notice a new weed threatening their flowers, lawns, and vegetables. But similar to dandelions or clover, this weed was actually quite pretty, with its purple-red steams, big leaves, and foot-long heads of delicate, tiny white flowers. But these weren’t harmless weeds—this was giant hogweed.
Giant hogweed is one of the most invasive if not aggressive plants on Earth. A single plant can grow to be as much as 20 feet tall. Tiny pods on the plant hide a toxic sap, which does its damage more than a day later. Skin touched by the sap that then comes into contact with sunlight turns red in 24 hours, followed by swelling, inflammation, and a terribly painful burning sensation three days later. If the sap gets in the eyes, it can burn the cornea, leading to temporary or even permanent blindness.
Present in Vancouver for decades, it’s spread across Canada, all the way east to Toronto, Ottawa, even hopping over to the maritime provinces. Cities are spending hundreds of thousands to dispatch teams of landscapers to destroy giant hogweed growing on public land—dressed like nuclear plant workers in head-to-toe protective gear, thick gloves, and masks.
Unfortunately, mowing it down or removing it from the roots (which are thick but shallow, allowing it to thrive around waterways) doesn’t do much good to stop the onslaught of giant hogweed. One mature plant can produce 50,000 winged seeds, which spread through the air and settle into the soil…where they’re viable for as much as 15 years.
So if you see got a towering, white-flowered weed in your yard this spring…don’t touch it and call city hall.