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UI Extension Publications and Multimedia

Western Waterhemlock in the Pacific Northwest

Product Details
PNW 109
Pub. Date: 2013

Online Only

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Western waterhemlock (xCicuta douglasii) is the most poisonous plant in North America—a piece of root no larger than a walnut can kill a mature cow. Every part of the plant is toxic. To help farmers, ranchers, and other landowners avoid the deadly plant, this publication provides an overview of it, including descriptions and color photographs to help identify the plant, which grows in wet places along streams, irrigation ditches, and sloughs in the western United States and Canada. It also provides management strategies, including herbicides and careful land-clearing practices, and some safety advice because its toxicity transfers on contact so readily.

Authors: Dale K. Whaley, Gary L. Piper, Robert Parker, Dwight Peabody

6 pages

University of Idaho Extension


Physical Address:
E. J. Iddings Agricultural Science Laboratory, Room 10
606 S Rayburn St

Mailing Address:
875 Perimeter Drive MS 2332
Moscow, ID 83844-2332

Phone: 208-885-7982

Fax: 208-885-9046



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