Giant hogweed is a close relative of cow parsley originally from southern Russia and Georgia. It can reach over three metres in height. Although this striking plant can be attractive, most gardeners will want to eradicate it. It is potentially invasive and the sap can cause severe skin burns. It is widely distributed in the wild and poses a serious risk to people who are unaware of its potential for harm. How hogweed is treated Treatment of hogweed is usually carried out in June and July when it is in full growth. Qualified staff use a spray containing Glyphosate, with a follow up treatment in September if needed. After 7 to 10 days the plants will wilt and they are left where they are to die off. Disposal of hogweed Giant hogweed is a controlled waste similar to Japanese Knotweed. It should only be removed from a site and taken to a licensed landfill site with the correct paperwork. What to do if see hogweed growing by a road or in a park Report hogweed to the council What to do if the hogweed is growing on private property such as a golf course or residential area If giant hogweed is located on land or property in Wirral the council will inform the land owner or tenant.