The Giant Hogweed is considered a noxious weed. Its scientific name is Heracleum mantegazzianum. It lives in Washington State. It is considered noxious because of its potential to take over other plant life and negatively impact the state of Washington's resources. It is a requirements for both private and public landowners to control this weed when it occurs on their land. It has a potential to harm humans so it is recommended that an expert be called in to do this safely. It is also somewhat difficult to identify since it looks a lot like the native plant, the cow parsnip.
The Giant Hogweed is from the Asian continent originally. It was introduced as an ornamental plant. It spread by seed and quickly escaped into backyards, parks, streams, abandoned lots, woods and roadsides. It crowds out all other plant life andtakes over natural areas. It is particularly fond of moist areas along side streams and creeks. The Giant Hogweed can survive in full sunlight and light shade. It will even invade and damage healthy grass if left untouched.
This weed is a public health hazard. It has a sap that has toxins that cause photo-dermatitis (a skin condition that causes the skin to be light sensitive and it can react quite violently with sunlight). This sap is a clear, watery looking liquid. When the skin is exposed to sunlight after the sap has contacted it, painful blisters will develop and can leave black or purplish scars.
The Giant Hogweed is a member of the parsley family. Its size is the most unique feature. It can reach a height of ten to fifteen feet when in full flower. This weed has hollow stems that are from two to four inches in diameter. The stems have stiff bristle like hairs and dark red to purple raised spots. They also have white stiff hairs at the base of the leaf stalk. The leaves themselves can be an impressive five feet wide. This plant bloomsfrom Many to July. The Giant Hogweed lives from five to seven years and is considered a perennial.
The flowers are white and clustered. They have an umbrella shape and can be up to two and a half feet wide with a flat top.
This plant is more of a problem in Great Britain than in the United States , but strict control is necessary to prevent it from spreading further.