Along with warmer weather and abundant sunshine, summer brings more threats from toxic plants. One of the deadliest is a non-native species of plant that is rapidly spreading across Ohio: poison hemlock. And it grows in every Ohio county.

Effects of Poison Hemlock

All parts of the poison hemlock plant are toxic, according to the U.S. Department of Agriculture (USDA). This includes the leaves, stem, fruit and root.

There is no antidote for poison hemlock, and ingesting it can be fatal. People can ingest the plant toxin through their eyes, mouth, nose or a wound – when they rub their eyes, touch their mouth or eat with their hands after coming into contact with poison hemlock, for example. People have even been poisoned by eating hemlock after mistaking it for wild carrot.

Poison hemlock toxin also can be ingested through the air if people make the mistake of burning or mowing the plant.

Initial symptoms of hemlock poisoning can appear anywhere from within 15 minutes to hours after ingesting the poison. Poison hemlock does not cause a rash. Instead, symptoms can include trembling, dilated pupils, confusion, dry mouth or excessive salivation, rapid heartbeat and high blood pressure, seizures and tremors, vomiting, sweating, lack of coordination and confusion.

In severe hemlock poisoning, the person experiences slowing neurological functions, coma, kidney failure, low blood pressure, muscle breakdown, muscle death, muscle paralysis, respiratory paralysis and slow heartbeat.

Call 911 or Seek Emergency Treatment

Get medical attention immediately if you suspect you or a loved one has ingested poison hemlock. Call 911 or go to the emergency department right away.

Do not delay. Immediate treatment offers the best hope for surviving hemlock poisoning.

How to Prevent Hemlock Poisoning

According to the Ohio Department of Natural Resources (ODNR), poison hemlock’s flowering period in Ohio can range from early April through early July. Its fruiting period is from June to September.

Poison hemlock can grow from 4 to 8 feet tall. Its tiny white flowers form umbrella-shaped clumps. Poison hemlock can be recognized by its smooth, purple-spotted stems and fern-like dissected leaves.

Keep the following precautions in mind:

• Treat all wild members of the carrot family as being potentially fatally toxic, since poison hemlock is so difficult to distinguish from other members of the carrot family.

• Do not touch poison hemlock without gloves. Thoroughly wash any areas of skin that have come into contact with it.

• Get rid of the plant as soon as you can. Ohio law mandates that people remove noxious weeds, including hemlock, from their property. By June, it is too late to effectively control it; you should contact an expert for removal. The ideal time to control poison hemlock is in late winter and early spring, since herbicide does not work on the plant once it has flowered. Map out where you have seen poison hemlock on your property, watch for the young plants in late winter and early spring, and be ready with herbicide.

• Do not mow, burn or cut poison hemlock. Never leave it in a compost pile; the plant parts remain poisonous even after the plants are pulled.

Visit The Ohio State University Extension website for more information on controlling poison hemlock.

Sources:
The U.S. Department of Agriculture
Ohio Department of Natural Resources
The Ohio State University Extension