By Andi Anderson
Poison hemlock, a toxic and invasive weed, is increasingly seen along roadsides, pastures, and field edges.
It closely resembles wild carrot (Queen Anne’s Lace), but can be identified by its hairless, hollow stems with purple blotches and finely divided leaves. It is a biennial plant, forming a rosette in year one and a tall flowering stalk in year two.
According to Ron Rathfon, Regional Extension Forester at Purdue, the plant is extremely dangerous. “The biggest risk with poison hemlock is ingestion,” he warned. “Lethal doses are small, and toxins can also be absorbed through the skin and lungs.” Wearing gloves and a mask is strongly recommended when handling the plant.
Symptoms of poisoning include dilated pupils, slowed pulse, bluish lips, and paralysis, which can lead to death if not treated quickly.
Poison hemlock thrives in disturbed sites like ditches, stream banks, roadsides, and vacant lots. It can spread into pastures and hayfields, posing a threat to livestock. Farmers should prevent its inclusion in hay and monitor feed areas.
Rathfon noted that seeds spread easily through mowing and farm equipment. To reduce spread, mow infected areas before the plant produces seeds. However, mowing once may not be enough—multiple mowings might be required.
Herbicide control is most effective when the plant is still in the basal rosette stage, or during early flower stalk development.
Because of its risks, poison hemlock is listed as a noxious and invasive weed in many regions, including Indiana. Careful management and awareness are essential to protecting both humans and animals from this dangerous plant.
Photo Credit: gettyimages-zoomtravels
Categories: Indiana, Rural Lifestyle, Farm Safety