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Poison hemlock poses threat

An expert with Purdue University is cautioning local residents to beware of a non-native plant that has made its way to the United States — and Indiana.
Poison Hemlock, an invasive species that can sometimes be confused with the more common Queen Ann’s Lace, is poisonous from root on up, said Purdue’s Wabash County Extension Director Geoff Schortgen.

“All parts of the plant are toxic,” said Schortgen. “While ingestion will cause the most sever reaction, there are some individuals who are more sensitive to it than others.

“Skin exposure can vary from no reaction at all, to uncomfortable boils on the skin, similar to poison ivy. Irritation is most likely to occur when the sap gets on your hand and you touch sensitive places around the eyes and mouth. If you are exposed be sure to wash with warm soapy water.”

Schortgen said the plant’s leaves are fern like, and the flowers are made up of white clusters of blooms. “The difference in Poison Hemlock is that when it bolts, the stem can reach 10 feet tall and has a purple stem at the base,” Schortgen said.

“The purple of the stem fades to green as it approaches the top of the plant. Wild carrot does not have a purple stem, grows to about three feet and has an aroma similar to the carrots we eat. Poison hemlock has a rancid odor, especially when it is disturbed,” he said.

Schortgen continued by saying that Poison Hemlock is a biennial. “This means that in the first year of its life, it will take the form of a short bush. During the second year of its life, it uses the energy from year one to bolt and produce flower and thus seeds.”

Schortgen said spraying the plant with herbicide during its first year is acceptable, “just as long as you follow label instructions.” He said products that contain 2,4-D and triclopyr work best, especially when the plant is small, around late-April or early-May.

“If the plant matures into year two and flowers, then sprays might not control the plant quick enough before seeds are developed.”

Poison Hemlock is a native of Europe, Schortgen said. “Invasive species are those that are introduced to an area where they have no natural pressure (predators) to keep populations in check. An example of this would be Bush Honeysuckle. Poison Hemlock produces a large amount of seeds, which means each of the plants we see today will give rise to many more plants in the future.”

Schortgen said the tall white blooms started appearing around June 1 and articles have been showing up in some of the southern areas of the state. “I would like folks to understand that identifying the plant is key, that way you can avoid it. Controlling Poison Hemlock comes second. If you have any doubt, feel free to reach out to the extension office and always follow herbicide label rules and handle with care. In summary, treat it like you would poison ivy.

“Humans have the ability to identify and avoid the plant,” he continued. “The largest threat comes to livestock that has access to open pastures. Anyone who has open fields for livestock to graze needs to be scouting for this plant to make sure that the animals do not eat it. As mentioned before, ingestion will cause the most severe reaction.”