Poisonous plant rapidly spreading across Ohio: what to do if you see it

Yahoo

23-05-2025

COLUMBUS, Ohio (WCMH) – Ohioans may spot clusters of white flowers along roadsides or fence lines as a poisonous plant blooms across the state.
Poison hemlock is a flowering plant that is part of the carrot family and can be fatal if ingested by humans or animals. The weed prefers sunny and moist environments, often growing in fields, ditches and creek beds.
Typically three to eight feet tall, the plant has fern-like leaves and stems with purple or red markings. When the biennial plant is in its second year of life, it boasts white flowers. While the species can be spotted year-round, it is currently extra noticeable in Ohio, as it is peak blooming season, according to Rick Gardner, chief botanist with the Ohio Department of Natural Resources.
'We are now in the thick of flowering, at least for central and southern Ohio, and they're starting to bloom in northern Ohio,' Gardner said.
Poison hemlock is native to parts of Europe and Asia. It was originally introduced to North America in the 1800s as an ornamental plant, thanks to its aesthetically pleasing flowers. While the toxic plant has been documented in Ohio for centuries, it has been rapidly spreading in recent years.
'Within the last, I'd say, 15 years or so, it has skyrocketed or spread really fast throughout the state,' Gardner said. 'Hemlock is like other highly invasive plants; it has really high seed production.'
In Ohio, the poisonous plant is most abundant in the western part of the state, but it has spread to all 88 counties, according to the ODNR. The invasive species is also present every American state with the exception of Hawaii, per Montana State University.
Poison hemlock is known to look like wild carrot or parsley, but ingesting it could be a fatal mistake. Consuming any part of the plant can result in it attacking one's nervous system and heart, possibly resulting in death, Gardner said.
'It's not a plant you want to take lightly,' Gardner said. 'The chemicals, the poisons in the plant that help protect it from herbivores, if you're exposed to a fair amount, it can cause basically damage to your heart.'
Generally, the plant is only poisonous if ingested and people will not get a rash from touching it, according to the Cleveland Clinic. Even if someone does not eat the plant, they could have a reaction through breathing in airborne particles while mowing over it or sap flying in their eyes or mouth while cutting it.
Symptoms of hemlock poisoning can occur almost immediately after ingesting the plant, according to the Cleveland Clinic. Signs a person may have ingested poison hemlock include sweating, vomiting, dilated pupils, excess salivation, dry mouth, rapid heartbeat, restlessness, confusion, muscle weakness, twitches, tremors and seizures.
'If somebody says that they've been out mowing the yard and they're going through some fern-like plants with white flowers and they show signs of coughing or feeling sick, you should take them to the emergency room right away or call paramedics right away,' Gardner said.
Symptoms among animals include trembling, salivation and frothing, lack of coordination, dilated pupils, rapid pulse and convulsions. Both humans and animals can die within a few hours of ingesting the plant. While a healthcare provider can treat symptoms, there is no antidote for poison hemlock.
Ohio law mandates that property owners cut or destroy prohibited noxious weeds, including poison hemlock. Gardner said the easiest time to remove the plant is during its early stages of life, before it begins displaying flowers.
Small infestations of poison hemlock can be removed by hand. Gardner recommends that hands are protected with gloves, arms are protected with long sleeves and eyes are protected with safety goggles. Plants should be dug out, with the entire root removed. They should then be placed in a construction-grade trash bag and disposed of.
Once the plant begins displaying flowers, Gardner said hand-pulling the infested area is 'not an option' and herbicides should be used. Crossbow and Remedy Ultra has the best rating for controlling poison hemlock, followed by glyphosate (Roundup), dicamba and Cimarron Max, according to Ohio State University.
Gardner said he does not suggest mowing over the plant, since its particles can become airborne and be ingested.
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