The Curse of the Giant Hogweed

Canadian author Charlotte MacLeod wrote a mystery book of that title, featuring Pete Shandy, Professor Timothy Ames and Professor Stott going back in time to solve a mysteyr featuring giant hogweed. I always thought she made it up, but apparently it's true:

From the blog Infocult

Giant human-wounding plant invades Canada
A very large weed is invading Canada and attacking people. It's called heracleum mantegazzianum, or giant hogweed (you pick), and is on the move in Ontario. Like something out of a 1970s eco-horror movie, or Day of the Triffids, the Terrible H is spreading.


Size: maxes out at six meters. Yes, a twenty-foot-tall weed. Hence "giant" in the name.
Weapon: it oozes poison. The stuff's strong enough to burn flesh, or blind your eyes, even permanently.
Stealth: it can hide, and still get you.
"[exposure] could be inadvertent," [Jeff Muzzi, manager of forestry services for Renfrew County] said. "You might not even know it's here, [just] walk into it and happen to break a leaf. The next thing you know, you've got these nasty burns."

Growth: this anti-human weed is spreading energetically.
"It spreads primarily by seeds... [which] can be carried by vehicles, by people, by winds it could be a bird. It could be any reason at all and I think every plant will produce something to the tune of 500,000 seeds, so the spread potential is pretty big."
Yes, it is deemed invasive.

Canadians, you can only mutilate, kill, and ship so many people before you outrage nature herself!