The giant hogweed is hard to miss. The monstrous plant towers up to 15 feet tall, with a crown of white flowers the size of an umbrella. They burst into bloom between the last week of June and the first week of July—just in time to be the perfect dramatic backdrop to red-white-and-blue-themed parties.
But whatever you do, don’t touch it. The giant hogweed’s toxic sap could give you third-degree burns if you don’t get out of the sun and wash it off immediately. Like an anti-sunblock, chemicals in its juices disrupt your skin’s ability to filter out harmful UV rays. Get it in your eyes and you could go blind.
In places where hogweed has been around for decades, residents know its risks well. But while the majestic flower of the hogweed adds a courtly presence to any landscape, it is an invasive species—producing up to 120,000 winged seeds at a time. In the mid-1900s it expanded across New York state, carried on the riverways it likes to grow near. It hopped into nearby Pennsylvania, Ontario, and then on into Michigan. About 15 years ago it invaded Ohio. Today it’s found sporadically in more than a dozen states—and it’s still spreading, putting more people in harm’s way.