I just did a lot of research on H. mantegazzianum and wrote a blog post about it. I'll give you a short summary of why you need to know this plant well and then if you are interested you can read the full post in which I cite many, many sources.
"The sap of this plant will give a person a horrifyingly nasty and painful skin rash that will last for weeks. If the sap gets into a person’s eyes, it will cause blindness (one source says temporary blindness). The toxin in the sap is activated by UV rays (phytophotodermatitis). According to Midwest Invasive Plant Network, giant hogweed is a perennial herbaceous plant that, by the 4th or 5th year, produces a 7-15 foot flower stalk. Before then its form is a rosette that grows bigger and bigger each year until it is ready to produce that humongous flower stalk and gigantic flower umbels.
Why is this plant so dangerous? According to this CBC report, “The toxins in the sap can create what is known as “phytophotodermatitis” — basically an extreme sensitivity to sunlight. The effects of the toxins are not felt immediately, but once activated by UV rays, they can damage skin cells and cause lesions that look similar to burns.”"
It is related to common hogweed, poison hemlock and Queen Anne's lace (wild carrot).
New to Detroit. Looking to help out with current permaculture and urban farming projects. Here is my blog from when I was an urban homesteader in Ohio but I am continuing to post about our suburban adventures in Permaculture. http://crunchymamasurbanhomestead.wordpress.com/
Elissa Teal : I have Flagged this Thread for greater emphasis, And and personally aware of the danger to the uninitiated, Due to the spreading caused by the
road scraping actions of Snow plows Many invasives /volunteers have been widely scattered on main and back country roads !
Certainly not to make light of what you are saying, but Wild/volunteer Parsnip which is also highly ' Phytophotodermic' is widely scattered on the sides of road
beds in these areas and the related families should be something that triggers early warning type alarms ! For the Crafts Big AL !
Success has a Thousand Fathers , Failure is an Orphan
Elissa Teal wrote:I just did a lot of research on H. mantegazzianum and wrote a blog post about it. I'll give you a short summary of why you need to know this plant well and then if you are interested you can read the full post in which I cite many, many sources.