As spring arrives, bringing longer and warmer days, nature awakens from its winter slumber and with it, a few unwelcome visitors. Among them are two particularly invasive and toxic plants: poison hemlock and wild parsnip.

After spending the cold winter months in a semi-dormant rosette stage close to the ground, both plants are now ready to bolt (grow rapidly and bloom once again.)

I first encountered these two toxic plants last summer in Iowa, near the cornfields where l worked. While admiring the beauty of their delicate flowers, my then-supervisor warned us about their nature.

The contrast between their striking appearance and their poisonous potential left me questioning: How could something that looked so pretty be so dangerous?

Known as one of America’s most toxic plants, poison hemlock has small white flowers arranged in clusters (called umbels), fern-like leaves resembling those of a carrot top and a green, smooth, hollow stem with purple spots or blotches.

To protect itself from herbivores, it produces toxins that, when ingested or absorbed through the eyes or nasal passages, can cause a range of symptoms, including dizziness, excessive salivation, vomiting, respiratory failure and even death.

Wild parsnip, on the other hand, is identifiable by its bright yellow flowers arranged in umbels, a green hollow stem with deep grooves and lower leaves that resemble those of a celery plant. While not as deadly as poison, it can cause severe burns and blisters. Eye exposure to the sap can also lead to blindness.

Unlike many other invasive species that accidentally found their way into the United States, poison hemlock was intentionally introduced as an ornamental plant, valued for its evergreen basal rosettes, especially in winter. Conversely, wild parsnip was imported by European settlers as a root vegetable.

Both plants have widely spread across the country and can be found in urban areas, along railroad tracks, in agricultural fields, grasslands and nature trails, posing a threat to both humans and animals.

Poison hemlock and wild parsnip are members of the carrot family and are biennial plants, meaning they take two growing seasons to complete their life cycle. Proper identification is key to safely managing these plants and avoiding accidental ingestion.

So, what should you do if you encounter these toxic plants around your home?

For small populations of poison hemlock and wild parsnip, pull or dig up plants when the soil is moist. While poison hemlock is not toxic to touch, precautions should still be taken when handling the plant.

For wild parsnip, it is important to wear protective clothing, including chemical-resistant gloves, as contact with the plant can be harmful to the skin.

For larger populations of both plants, herbicide application before seed set is recommended. Regularly monitoring infested areas and cleaning equipment is essential to prevent seed spread.

By following these steps, you can effectively manage and reduce the spread of these invasive and toxic plants around your home.

Motswaledi is an OSU Extension educator for agriculture and natural resources in Mahoning County.