a tall plant, Heracleum mantegazzianum, of the parsley family, native to Russia and now naturalized in the U.S., having very large leaves and broad, white flower heads somewhat resembling Queen Anne's lace: can cause an allergic rash when touched by susceptible persons.
Unable to identify one plant growing on his doorstep, he leaves it alone and lets it grow: it turns out to be a giant hogweed.
In which they innocently planted the giant hogweed throughout the land.
Serial killers and giant hogweed would seem to have little in common.
giant hogweed makes an impressive appearance because of its height, and the size of the leaves and flower clusters.
giant hogweed causes blistering and severe skin reactions.
Spread the word to friends and neighbors about giant hogweed.
British Dictionary definitions for giant hogweed
an umbelliferous garden escape, Heracleum mantegazzianum, a tall species of cow parsley that grows up to 31/2 metres (10 ft) and whose irritant hairs and sap can cause a severe reaction if handled Also called cartwheel flower