This widespread Class C weed is found throughout Washington. It is acutely toxic to people and animals. In western WA, it is common on roadsides, in open fields, and in natural areas. Unrelated to the native evergreen hemlock tree, poison-hemlock can be deadly; it has gained notoriety through its use in the state execution of Socrates.

Poison-hemlock can be confused with wild carrot (Daucus carota, or Queen Anne's Lace), as with many other members of the parsley family that resemble it. While poison hemlock is similar to wild carrot, their differences are numerous. Poison-hemlock has smooth hollow stalks with purple blotches and no hairs on its stems. It can get quite tall, sometimes up to 8 feet or higher. It produces many flower heads in a more open and branching inflorescense. In contrast, wild carrot usually has one red flower in the center of the flower top and is usually about 3 feet tall, or less. Poison-hemlock starts growing in the spring time, producing flowers in late spring, while wild carrot produces flowers later in the summer.

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For more information on identification and control of poison-hemlock, please read the Poison-hemlock Weed Alert (144 kb, Acrobat file)

Links for More Information:

• Clark County, Washington Fact Sheet
• Cornell University Poison Plants Database (scroll down)
• Montana State University Extension
• Colorado State University Extension
• TNC Weeds Element Stewardship Abstract
• Guide to Weeds in British Columbia