Often confused with non-native giant hogweed, common hogweed (Heracleum sphondylium) is a native biennial or short-lived perennial wildflower (often classed as a weed), found in hedgerows, roadside verges, allotments and waste ground. So-named as it was once used as pig fodder, it bears large, plate-like clusters of cream-white flowers from May to August, which attract a huge range of insects, particularly flies. It has hollow, hairy stems and large hairy, divided leaves. Its stems persist after the plant has finished flowering, and may be used by nesting solitary bees the following spring.
Like giant hogweed and similar looking cow parsley, it's a member of the carrot family (Apiaceae). Like giant hogweed, its sap is toxic, although far less so. While touching its sap won't cause burns as significant as those of giant hogweed, it's advisable to wear gloves when handling and wash hands after contact.
How to identify common hogweed
Common hogweed is a tall-growing plant, reaching heights of up to 2m. Its flowerheads can reach 20cm across and its rounded leaves can be up to 60cm in length. It has hairy, hollow, and grooved stems. It's often mistaken for giant hogweed, which can grow up to 5m in height and has more pointed leaves. It's also sometimes mistaken for cow parsley, which has more finely divided, filigree leaves.