Japanese knotweed, Cow Parsley, Ground Elder, Knotweed, Borscht
Heracleum is a genus of about 60 species (depending on taxonomic interpretation) of biennial and perennial herbs in the carrot family Apiaceae. They are found throughout the temperate northern hemisphere and in high mountains as far south as Ethiopia. Common names for the genus or its species include hogweed and cow parsnip.
Major species include:
Heracleum mantegazzianum, Giant hogweed, is a native of the Caucasus Mountains, grows to 4–5 m tall, and can cause severe phytophotodermatitis if the sap gets on human skin. The main mechanism for this dermatitis is extreme photosensitivity, causing severe sunburn on exposure to relatively small amounts of sunlight, with rash and blistering appearing within a few minutes: accordingly immediately covering sap-affected skin can prevent the dermatitis in many cases. It has become a serious invasive weed in many areas of Europe and North America, after being introduced as a garden plant.
Heracleum persicum, Persian hogweed, is similar in size and properties to the giant hogweed, and was originally from Iran, Iraq and Turkey; it is known in northern Norway as the Tromsø palm.
Heracleum nepalense is common in Sikkim and Darjeeling district of India. Called chimphing in the Nepali language, it is considered medicinal for stomach ailments and its seeds are ground with tomato and taken as a relish, especially with boiled vegetables.
Species
Note that this is a full list of the 187 names described in the genus; the majority of these names are treated as synonyms of earlier-described species by most botanists.
