Wanted for: bullying British wild plants by invading wasteland and riverbanks, forming dense colonies. This goliath among plant leaves the Brits standing in the shade!
Originally from: Caucasus Mountains, South West Asia. Introduced as an ornamental in 1893.
Latin name: Heracleum mantegazzaneum
Distinguishing features: this giant umbellifer can grow up to 5m tall with lower leaves up to 1.5m long and flower heads up to 0.5m across. It has purple blotches on its stem. Danger! If sighted, do not touch - can cause painful blistering, leading to eventual scarring.
Super Invasive Powers: each flower head produces up to 50,000 seeds that are dispersed rapidly along water courses. Seeds may remain viable for up to 15 years!