Hole in the Clouds


Invasion of the Giant Hogweed

Jul 11, 2012

Giant hogweed has spread from the Caucusus region of Russia across central and northern Europe and now across the northern United States and Canada. It's an invasive species that takes over roadsides and the edges of pastures and creekbanks. You don't want it near you.

It doesn't look so bad. It's got big, toothy leaves that green up very early in the spring around a central stalk that can grow ten or twelve feet tall, topped by lacy white flowers. But it's a terrible neighbor, full of bad habits. Even its early spring growth is problematic, because its leaves shade the ground all around, stunting or killing the native grasses and other plants. If it spreads to a creek or riverbank, its shallow root system can lead to rapid and severe erosion.

Cows don't like the taste of it, and that's a good thing for the cows. People, on the other hand, don't know to stay away. They might brush up against it as they are walking by. They might even pick the flowers. Children have been known to use the stems as pea shooters. None of this is a good idea.

Giant hogweed produces chemicals that make skin extremely sensitive to sunlight. If you touch any part of the plant and then stay out in the sun, you will wake up the next morning with severe, blistering sunburn.  If the hogweed touched the eyes or mouth, the resulting burns can cause permanent tissue damage, even blindness. Fatalities have occurred.

As shown above, giant hogweed eradication efforts can involve serious herbicides and hazmat suits. Some infestations are best countered with a herd of goats; goats eat the weeds happily, especially in early spring when the leaves are still tender and small. In either case, the hogweed will grow back and must be attacked repeatedly for at least a couple of years.

landscape   weed   invasive species   herbicide