Farmers face threat from famous plant

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Poison hemlock spreading in hayfields, pastures in several areas of the county



PERRY COUNTY – A new weed with a famous history could cause local livestock farmers big trouble this year and in growing seasons to come.

Poison hemlock, found for several years along Interstate 64 and in ditches, is increasing and invading hayfields and pastures. It could cause livestock deaths for producers who fail to recognize it and allow their animals to graze on it or who feed it as hay.

Poison hemlock is native to Europe but was introduced as an ornamental plant in the U.S. more than a century ago and has spread quickly.

The plant has been famous since Socrates was executed by asking him to drink a potion made from it in 329 B.C. But today, the owners of cattle, horses and other grazing stock could pay the price if their animals eat the plant.

“It’s growing fast and tall in a lot of areas and it can certainly kill livestock,” one northern Perry County farmer said during a tour of farmland in the Leopold and Oriole areas. “People need to know what it is but I worry a lot of them don’t.”

Poison hemlock, which carries the Latin name Conium maculatum, resembles another local weed, the wild carrot.

Like the wild carrot, poison hemlock is a biennial. This means that it lives its life over two years. In the first year, poison hemlock goes through vegetative growth. In the second year, it will produce small white flowers arranged in umbrella-like clusters, similar to wild carrot. It is in the second year, when it bolts and flowers, that it tends to catch the eye.

In fertile soil, the flower stalks can grow up to 8 feet tall. Both poison hemlock and wild carrot belong to the parsley family (Apiaceae). Both have the characteristic small, white flowers and leaves that expand at the bases sheathing the stems.

Larger plants often have purple blotching on the stems.

Local farmers should know how to recognize poison hemlock and keep cattle from grazing on it. Like some other plants, the toxic chemical in leaves and stems can be more dangerous when the plant dries. Coniine, the active ingredient in the plant, causes paralysis of the muscles, including those used for breathing.

All parts of the plant are poisonous, including the leaves, stems, seeds and roots. Simply handling the plant can cause toxic reactions in humans.

According to extension ag educators, poison hemlock is best controlled when plants are small. Herbicides such as 2,4-D, triclopyr, and glyphosate (Roundup) are effective.

Gardners and small farmers can pull out young plants by hand. Experts suggest using gloves when handling the weed since the poison can be absorbed through the skin.

Control is best done when the plant is relatively small and before they produce seedheads. Seed can be carried by birds or by rain to new areas.

One large field east of Leopold had several large clumps of poison hemlock growing in it.

While animals avoid eating the plant because of its taste, poisoning does occur and farmers should not bale hay from fields in which hemlock is growing.

Livestock will sometimes eat the plant during drought conditions when other forage is unavailable.

Even if not killed by the plants, livestock can suffer abortions and other reproductive problems.

Parents should also be aware of the plants, if found growing in their areas.

There have been cases where children have been poisoned by using the plant’s hollow stems as pea shooters.