Lookalike guide
Giant hogweed vs Common hogweed
Common hogweed is everywhere on Swansea verges. Giant hogweed is far bigger and far more dangerous.
Common hogweed (Heracleum sphondylium): Native — sap can still irritate skin.
| Feature | Giant hogweed | Common hogweed |
|---|---|---|
| Height | 3–5 m | Usually under 2 m |
| Stem | Thick, with dark purple blotches and stiff bristles | Green, ridged, softly hairy, few blotches |
| Flower heads | Up to 50 cm or more across | Around 15–20 cm |
| Leaves | Sharply jagged, up to 1 m+ | Rounder lobes, much smaller |
Quick test
If it towers over you with blotchy purple stems, keep away and report it. Do not touch either plant bare-handed.