Hogweed: An Invasive Plant With A Nasty Sap
Great landscaping and stunning gardens can turn a yard into a wonderland. Many gardeners and gardens turn to other parts of the world to find beautiful and exotic plants for their yard. Exotic plants have led to many beautiful gardens and some giant headaches. A lot of plants from elsewhere escape from domestic gardens and go rouge. There are some plants that have established themselves in the North East of the United States. Boston landscaping and MA landscaping in general have had close calls with problematic plants. One of the most threatening species is Giant Hogweed.
Giant Hogweed, (Herculeum Mantegazzianum) has been found in Massachusetts and other other states. It is an aggressive plant that quickly pushes out native plants and modifies habitats. It looks like Cow Parsnip (Herculeum Maximum) in the land of giants. While Cow Parsnip is a large decent sized plant averaging 4-5 feet in height with the ability to grow to 8 feet, the Giant Hogweed is, well, giant. It can tower between 10 and 15 feet tall with huge flowering heads measuring 2 and a half feet across. Its leaves can spread up to five feet across. It is an impressive plant that turns people into Lilliputians . It’s the impression one gets walking beneath them.
Giant Hogweed is a native plant of Central Asia and the Caucasus Region. Hogweed has taken over in parts of Britain and has invaded the Northeast and Northwest regions of the United States. Aside from its aggressive growth and habitat invasion, the Giant Hogweed is also a noxious weed harmful to animals and humans. The sap of the Giant Hogweed is clear and watery. It is also a phototoxic weed. It’s not a threat to photography, but it could cause some serious damage to your skin. Phototoxicity means that the sap interacts with sunlight, mainly the ultra violet rays. This often results in severe itching, blistering and even scaring that lingers for many years. If the liquid from the plant enters the eye, it can result in blindness. The plant has a chemical, derivatives of furocumarin, whichwork there way into epithelial cells, attach to the DNA and cause the cells to die. This is much like a chemical burn and chars the skin deep brown.
Since it is both invasive and toxic, it has earned a spot on the Federal Noxious Weed list and is slated for eradication wherever it is found.
Since Common Cow Parsnip and Giant Hogweed, (also referred to as Giant Cow Parsnip) look alike, it is important to know the differences. The first noticeable difference is the size. But both are tuberous recurrent plants. This means that they die back each winter and send up new shoots in the spring. Because Herculeum Mantegazzianum doesn’t start out 15 feet tall it’s essential to understand some of the differences. The distinctive marks of Giant Hogweed is purple spots on on a hollow stalk that can grow from 2 to 4 inches in diameter. Cow Parsnip has no spots and the hollow stem rarely gets bigger the 2 inches. Herculeum Mantegazzianum has short hairs underneath its leaves while Cow Parsnip has a profusion of long hairs.
If you discover a patch of Giant Hogweed, don’t hesitate to get in touch with the appropriate local agency or the Department of Natural Resources. Giant Hogweed should be approached in the same way one would approach poison oak and poison ivy, washing with soap and water and staying clear when possible.
