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Beware of Dangerous Carrots!

Written by Rhonda Ferree, retired horticulture educator

While on a recent motorcycle ride with my husband Mark, I saw a lot of plants in the carrot family Apiaceae growing along roadsides. One of my favorite vegetables is the very edible carrot, but unfortunately the carrot family has a number of dangerous, poisonous plants in it too.

The first two dangerous carrots I'll cover are stomach poisons, which means they are poisonous if eaten.

Poison hemlock (Conium maculatum) is not native to Illinois and was added to the Illinois Exotic Weed list in 2015. It grows four to nine feet tall with four to six inch white flowers. It has a purple spotted, waxy stems. This is the plant I saw most on our ride. I could also smell it every time we rode past a good stand of it, which was usually at bridge crossings. Poison hemlock has a disagreeable "mousy" odor. The entire plant is poisonous if ingested.

Water hemlock (Cicuta maculate) is considered by many to be the most poisonous plant in the northern temperate zone. Only a small amount of the toxic substance in the plant is needed to produce poisoning in animals or in humans. This native plant grows three to six foot tall with 6 inch white flowers and purple-streaked stout stems. All parts of this plant are poisonous, especially the roots.

The next three dangerous carrots cause photo-dermatitis. Cow parsnip, wild parsnip, and giant hogweed contain an allergen that is activated by sunlight to cause rash, blisters, or other skin irritations in susceptible people.

Cow Parsnip (Heracleum lanatum) is a native plant that can reach eight feet tall. Like the hemlocks, its flowers are white, but cow parsnip flowers are larger, growing to 10 inches across. The large flowers were obvious as we rode past them on the motorcycle.

Wild Parsnip (Pastinaca sativa) has large yellow flowers that are about five inches across. It is a stout plant that grows to five feet tall with grooves along its stem. I know a few people, including my sister, whom are very allergic to this plant.

Giant hogweed (Heracleum mantegazzianum) is the worst of the three that cause blisters in the sun. This plant lives up to its name as a giant. It grows 15 feet tall with five foot leaves and 2 ½ foot white umbel flowers. Its massive size makes it desirable to some home gardeners, but it is a public hazard that causes severe skin irritation in susceptible people. A USDA pamphlet says this plant's sap produces painful, burning blisters that later develop dark scars that may persist for years. Fortunately, it has only been found in an isolated location in northwest Illinois, and those plants have been eradicated. Giant hogweed is a federal noxious weed, making it unlawful to propagate, sell or transport this plant in the United States.

Finally, not all carrots are dangerous. Queen Anne's Lace (Daucus carota) is also called wild carrot due to its large, edible taproot. It grows four foot tall with lacy four inch flowers. This plant is the ancestor of our cultivated carrot, though its roots are white instead of orange.

Other edible plants in this family grown for their roots are parsnips and bulb fennel. Anise, caraway, celery, chervil, cicely, coriander (cilantro), cumin, dill, fennel, and parsley are grown for their edible leaves and seeds.

Think I'll eat a salad with lots of carrots for lunch!



As horticulture educator, Rhonda Ferree inspired citizens in local communities to grow their own food and improve their home landscapes. She focused on high quality, impactful programs that taught homeowners how to create energy-efficient landscapes using sustainable practices that increase property values and help the environment.

After 30 years with University of Illinois Extension, Rhonda retired in 2018. She continues to share her passion for horticulture related topics as “Retro Rhonda” on social media.

ILRiverHort is a blog that helps people connect to nature and grow.