Hogweed is a very common roadside verge umbellifer in flower during the height of summer but can flower all year round. People, particularly children should be aware of the dangers of this plant. Last week our caretaker, Annie Wilkinson was strimming a verge in Thorgill for road safety reasons and strimmed Common hogweed Heracleum sphondylium. The sap from the plant sprayed on to her arm and caused serious and extensive blistering which subsequently required medical attention. On the sunny day the reaction was made worse because the skin is hypersensitive in bright sunlight. Common hogweed isn’t much more than 2m tall and the stem no more than 5cm thick.
There is the possibility the hogweed could be Giant hogweed Heracleum mantegazzianum and whilst this should not be ruled out completely examination of the plant suggests this unlikely.
Giant hogweed, which is usually found along river systems but not always, has been in the press recently due to its aggressive and invasive spread through the countryside and like Common hogweed contains the harmful sap. However, Giant hogweed is a much greater danger as reaction to its irritant chemicals in the sap is more severe. Even just brushing against the bristles on the stem or leaves can cause severe skin irritation and getting sap in the eyes can cause blindness. Giant hogweed is a huge plant, growing well over 3m tall with very large flower heads and thick stems of over 10cm. There is a really useful guide to identification of Giant hogweed under Species information at nonnativespecies.org. Whether it is Common hogweed or Giant hogweed exercise extreme caution or stay well clear. Updale Natural History Recorder