Noxious Weeds

Yesterday I wrote about my experience so far with velvetleaf.  This weed is classified as being noxious in British Columbia and several US states.  To be classified as a noxious weed the plant has to cause harm to human via toxicity or cause an agricultural loss however every municipality has their own definition of noxious weeds.  In some localities a weed (eg. water hyacinth) can be classified

Giant Hogweed

Warnings have been issued for southern Ontario regarding giant hogweed (Heracleum mantegazzianum) aka giant cow parsley.  This is a  perennial, invasive noxious weed that reaches a height of 5 metres is a public health risk.  The sap contains furocoumarin, a chemical that renders skin extremely susceptible to UV exposure resulting in severe burns and blistering (phytophotodermatitis).  This can