Land Plants - invasive

Poison Hemlock (Conium maculatum) on Jun 26, 2018

Originally reported as Giant Hogweed (Heracleum mantegazzianum)

Submitter does not have a specimen
EDRR Status: No Response/Action Required

Description of specimen

2 large giant Hogweed plants, ~7 feet tall each in full bloom.
There were previously half a dozen on the opposite side of the street that have since been cut down. But two large plants remain on one side of the street. I have seen them here for 2-3 summers, so they have established somewhat of a foothold here.


Thanks so much for reporting this suspicious plant Timothy. Fortunately this is not giant hogweed, but a distantly related plant called poison hemlock. It is also a noxious weed, but is very common in Oregon. This one is poisonous if ingested, but will not cause serious burns to the skin like giant hogweed (although it could still be irritating to the skin). If you would like to get more information about noxious weeds in your area you can contact Mitch Bixby with the City of Portland's invasive plant program at or, if you are outside the city limits, Michelle Delepine with West Multnomah Soil and Water Conservation District at

Beth Myers-Shenai
July 5, 2018, 7:51 a.m.