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Poisonous plants pose threat to livestock

Published on June 10, 2011 3:01AM

Last changed on July 8, 2011 10:19AM

Doug Warnock

Doug Warnock

Doug Warnock/For the Capital Press
This group of poison hemlock was found near a wheat field in Eastern Washington.

Doug Warnock/For the Capital Press This group of poison hemlock was found near a wheat field in Eastern Washington.


For the Capital Press

Having recently found some poison hemlock at the edge of our field, I urge livestock producers to learn to recognize and look out for poisonous plants. There are a number of plants that have toxicity, either at certain stages of growth or throughout their life. Two of the more serious in the Northwest are poison hemlock and western water hemlock.

Poison hemlock

Poison hemlock, Conium maculatum, which looks like a carrot plant and is often mistaken for wild carrot, is a member of the parsley family. It is often found along the edges of fields and pastures, roadsides, ditches and sometimes even gardens.

An erect biennial plant that grows to six feet or more in height at maturity, it has many tiny white flowers in umbrella-like clusters. Its stems are smooth and hollow with purplish-speckled spots. The purple spotting is a distinctive feature that helps in identification. It also has an unpleasant, "mousy" odor. While it resembles wild carrot, it does not have hairy leaves like wild carrot, but has leaves that are hairless.

Poison hemlock is highly toxic and potentially fatal, especially for children who may mistake it for parsley or its roots for carrots. It is toxic to both humans and animals. It can be found throughout the northern United States and Canada.

Water hemlock

Western water hemlock, Cicuta douglasii, is thought by some authorities to be the most toxic plant in the north temperate zone. It is in the same family as parsnip, carrot, celery and wild edible roots such as wild caraway or yampah. This perennial grows on damp ground and in shallow water.

An erect plant, with a mature height of 3 to 7 feet, it has leaves with many toothed segments. The leaf veins extend directly to the "v" between the teeth rather than to the tips of the leaves. Its large, fleshy root is divided internally by cross partitions, which give it a very distinctive ladder appearance when cut open.

The entire plant is poisonous, especially the roots and rootstock. It is sometimes mistaken for edible look-alikes with deadly results. Children have been poisoned from using the hollow stems as peashooters or whistles. Plants of this species should be pulled, dried and burned. Livestock have been poisoned by ingesting plants that were pulled and dried, so burning is necessary.

Livestock managers as well as landowners should be able to recognize plants that are potentially dangerous and be on the lookout for them to avoid loss of valuable animals and reduced revenue.

For more information contact Patricia Talcott, Washington Disease Diagnostic Laboratory at Washington State University, at 509-335-0807 or ptalcott@vetmed.wsu.edu .

Doug Warnock is a retired WSU Extension agent.


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