Western Water Hemlock
(Cicutta douglassi)


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The Western Water Hemlock grows small white flowers in clusters called umbels

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Detailed image of the fruits of a Western Water Hemlock Plant

The Apiaceae Family

The Western Water Hemlock is a member of the Apiaceae family, better known as the carrot or parsley family. Surprisingly,this family contains some well-known edible plants and spices such as cumin, celery, and dill. However, it also does have a killer relative in the Poison Hemlock, the plant famous for killing Socrates. The Poison Hemlock appears to be similar to Western Water Hemlock, but grows slightly taller with a poison that is close to, but not as strong as the Water Hemlock.The quality of these plants that make them easily identifiable is their compound umbels. An umbel is simply a group of flower stalks that are of equal length and curve inward from the center to form an umbrella like shape. The fact that flowers in the Apiaceae family have compound umbels means that there are several levels of umbrella shaped stalks protruding from one shared point. It is important that anyone attempting to identify a member of the Apiaceae family is a skilled botanist or has the help of one, because what one might think is an edible plant, could actually be a lethal poison.

Dill has compound umbels just like the Western Water Hemlock
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Looks extremely similiar to Western Water Hemlock, but Posion Hemlock typically grows a few feet taller
Also looks similiar to Western Water Hemlock, but this is cumin, another edible member of the Apiaceae family

Geographic Distribution

Western Water Hemlock is found predominately throughout the Pacific Northwest and parts of Canada. This plant has a high water capacity, so it grows in and around wet areas such as streams, rivers, and ditches.

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The toxic part of the Western Water Hemlock is found in the oil of its root-stalk. Its oil contains a cicutoxin (an unsaturated alcohol), which gives off a carrot like odor, that when coming into contact with the air turns a bright orange-yellow color. While the green seed heads of this hemlock are posionous, the most poisnous parts of this plant are its roots. The cicutoxin is so lethal because it attacks the central nervous system and will cause effects even when taken in amounts 0.1% of an organisms body weight. Signs that one may have ingested Western Water Hemlock include dizziness, nausea, drooling, vomitting, and trouble breathing. There is no evidence that this plant can be used to aide humans in any way.

Why Would This Plant be so Poisnous ?

The Western Water Hemlock does have a method behind its madness in that it did not randomly develop this lethal poison, but developed it as a defense mechanism to avoid extinction. The Western Water Hemlock would seem like an ideal source of food for livestock because of its location near a water source and the fact that it is one of the first plants to develop in the spring. Besides being a target of livestock, it also had to be concerned about humans who may mistake it as a different edible member of the Apiaceae family. Therefore, it may have needed to develop a toxin to ward off its predators and stay on the map.

Methods of Control

Considering that the Western Water Hemlock is deemed the most "violently toxic plant that grows in North America" by the USDA, there is a great deal of focus on how to contain the plants growth and how to remove the plant entirely in order to keep the public and livestock safe. One can go about protecting their family and/or livestock from the posionous plant by using either manual methods or chemical killers. If one is wary to spray pesticdes on the Western Water Hemlock in fear of killing plants around it, they may decide to remove the plant by hand when the ground is wet. It is important to note that protective gloves must be worn during this manual process and it is essential to have all roots disposed of, as livestock will otherwise attempt to chew them. Also, livestock should not be allowed anywhere in the area for weeks after removal in order to prevent them from drinking the poisoned water. The alternative to the laborious hand removal process, would be to use a herbicide containing the ingredient glyphosphate or imazapyr. Products such as RoundUp Pro that do contain glyphosphate, must have it mixed to a concentration of 2%. This solution should be sprayed on the leaves in an amount that makes them wet, but not dripping. Imazapyr, which is found in prodcuts such as Arsenal, is more potent than glyphosphate as it has the potential to kill all plants that come into contact with. Thought exteremely effective in fighting Western Water Hemlock, herbicides containing impazapyr should only be used in large areas dense with the plant, as to not kill vegetation around it. Again, livestock and humans should not go anywhere near the area of spraying for two to three weeks following. While the Western Water Hemlock is an extremely poisnous and dangerous plants, there have been concentrated efforts to contain and remove the plant in humane fashions.

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RoundUp Pro is an example of a herbicide that can kill Western Water Hemlock because it contains glyphosphate as an active ingredient.
Imazapyr is a strong ingredient that has the ability to kill Western Water Hemlock on a widespread level.


Cicuta douglassi In (2012). Wikipedia. Wikipedia. Retrieved from http://en.wikipedia.org/wiki/Cicuta_douglasii

Coult , J. M., & Rose (2012, 12 03). Cicuta douglassi . Retrieved from http://plants.usda.gov/java/profile?symbol=CIDO

Elpel, T. J. (n.d.). Apiaceae parsley or carrot family. Retrieved from http://www.wildflowers-and-weeds.com/Plant_Families/Apiaceae.htm

Graham , J., & Johnson , W. S. (n.d.). Managing poison and western water hemlock. Retrieved from http://www.unce.unr.edu/publications/files/nr/2004/fs0409.pdf

Integrated Pest Management Prescription. (2006, 02 07).Western water hemlock (cicuta douglassi) . Retrieved from http://www.co.thurston.wa.us/health/ehipm/pdf/water_hemlock.pdf

Web M.D. (n.d.). Water hemlock. Retrieved from http://www.webmd.com/vitamins-supplements/ingredientmono-948-WATER HEMLOCK.aspx?activeIngredientId=948&activeIngredientName=WATER HEMLOCK