Even the name insinuates the most noxious, insidious killer to lately crawl out of Asian cargo ships onto our purple-mountain majesty coasts: The Giant Hogweed!
It’s heeeeere! 
It’s native to Central Asia and it’s spreading toward the northeast. It’s already established in Michigan and Indiana. New reports are showing the unwelcome visitor arriving in Pennsylvania and New York State.
The Giant Hogweed is an invasive species, a member of the carrot and parsnip family. (I knew there was a good reason why I hate carrots!!). However, this family member grows to be a lot taller than Bugs Bunny’s meal of choice. The hogweed can grow to be 15 feet tall and 15 feet wide. It produces a disgusting number of seeds, too, to ensure that it ruins as much property as possible. *sigh* The British initially brought the hogweed home from Asia in the 19th century, planting it as an “ornamental” plant in special gardens. But like The Blob, Jurassic Park, and Killer Bees, things *kinda* got out of control and the species escaped captivity. Oopsie.
The hogweed has lace-like flowers very similar to Queen Anne’s Lace. The leaves resemble large, jagged dandelion leaves and the plant would almost be pretty were it not for one small problem: it’s viciously poisonous.
The plant produces a sap that burns human skin. God forbid it should get in the eye, or blindness can occur. According to the University of Illinois Extension:
Characteristics include hollow stems, between two and four inches in diameter, with dark reddish-purple splotches and coarse white hairs. Leaves are compound, lobed, deeply incised and may grow up to five feet in width. Flowers appear from mid-May through July. As with other members of the carrot family, the flower heads are umbrella-shaped, up to 2½-feet in diameter across a flat top with numerous small flowers.
The Giant Hogweed is sometimes mixed up with other members of the parsnip/carrot family. My husband came home wondering if he’d seen a hogweed planted by a mailbox, but the flowers were yellow. I think he probably saw wild parsnip. Other very similar plants are cow parsnip, wild carrot, poison hemlock and angelica.
Giant Hogweed has a thick, tuberous stem with very wide white lace flowers. It exudes a clear, sticky sap that causes photodermatitis. Skin contact followed by exposure to sunlight can cause severe burns and blisters that become purple or black blotches and scar the skin. VERY nasty.
I just don’t know how the Chinese manage, with all these horribly toxic plants and bugs that float around over there. In my opinion, I’d rather manufacture our goods here in the U.S.A. and avoid all the extra baggage in the cargo crates. 
Anyway, the Giant Hogweed is a “federal noxious weed” and therefore it is illegal to propagate, sell, or transport the plant. Do not pull, mow, or chop down the weed with a weed whacker. Doing so will release the sap. And, since the plant is a perennial weed (which means it will grow again even after the entire planet has been decimated by nuclear war), the Giant Hogweed will just keep coming back for more. Think of this plant as Bishop Weed from hell.
If you see the Giant Hogweed, alert the authorities. Who ya gonna call? The GIANT HOGWEED HOTLINE! I’m putting this number in my speed dial, people: 845-256-3111. If you see hogweed, call them. A hazmat team will arrive via black helicopters and blow the smithereens out of the noxious weed. YEAH, BABY.
OK, I jest. A hazmat team is *probably* not required. Nor are the black helicopters, but hey– black helicopters have descended upon DVD pirates in the local ‘hood, so ya never know….. this is a “federal noxious weed,” after all….
Some photos and information courtesy of hyg.ipm.illinois.edu/article.php?id=80
:) I’m a married mom of four teenage children. We live in Upstate New York. We bought an old 1855 home and acre property, over 10 years ago. We've been in the slow, agonizing process of living in the home while (trying) to renovate it. When I'm not renovating, I'm a freelance writer and blogger.
We've learned to dig a French drain, plant huge flower and vegetable gardens, wire a circuit panel, install furnace ducting, understand the enigmatic complexities of the plumbing system, and more. It's been *quite* the adventure.
You can read more 
July 14, 2011 at 8:49 pm
We found out the hard way that rue is like that too–it causes burns if you try to touch it in the sun. We were cleaning up the yard for vacation one year and when we got in the car the next day, we were both covered in red burn marks all over our arms and legs. It took forever for the scarring to clear up.
EEEEKK!
June 13, 2012 at 12:47 pm
Something we already have right here in abundance is wild parsnip–this is the tall flat yellow flower (Like Queen Anne’s Lace also) seen roadsides around the 4th of July. And it too causes horrid sun-induced burns on the skin of *some* unlucky yard clearers. It doesn’t affect everyone, but we discovered the hard way that both the fellas in my family are affected. Left scars on my little boy for a couple years afterward… DO NOT TOUCH!