Among Northeastern Illinois’ weed list is a very dangerous plant called ‘Poison Hemlock’  (Conium maculatum) and should be removed very carefully from your landscaping promptly!

(Image from www.illinoiswildflowers.org.)

On this plant of the carrot family, you will notice that the flowers have 5 petals on each set.  The typical cluster is roughly 2-2.5″ across distinguishing it from Queen Anne’s Lace.  Also, Queen Anne’s lace has one red floret in the center of its flower cluster, poison hemlock does not (as seen above.)

(Image from phytophactor.fieldofscience.com.)

You will notice that the leaves of the Poison Hemlock plant look similar to the carrot.  The smooth stem is stout, has a ridged appearance and is marked with purple spots. The stem is hollow. Leaves are large and very ferny in appearance. (www.mortonarb.org)

(Image from www.ohioline.osu.edu)

Management: Plants can be cut down or dug out. This should be done before the plants go to seed and is most easily done when plants are small. Cover your skin during this process. Do NOT burn the plants. In spring, small, actively growing plants may be treated with an herbicide containing glyphosate.  (Please be very careful when handling glyphosate!) (www.mortonarb.org)

For more information, please visit the Morton Arboretum website, or visit http://hyg.ipm.illinois.edu/article.php?id=380